Why a Well-Written RFQ in Construction Still Cannot Prevent Vendor Overbilling?

Imagine a scenario where a procurement management at a mid-sized civil contractor’s summer in Pune ran what looked like a textbook RFQ in Construction process last year. The invitation to quote structural steel was sent to three vendors for commercial building projects. There were identical specifications across all three RFQs. Everything was defined. Delivery timelines, statement of payment terms, etc. The rates came back and were compared on a spreadsheet, and the lowest qualified vendor received the purchase order.

Six months later, a project cost review showed material spend running nineteen percent above budget. The procurement manager pulled every steel vendor bill from the project. Every single invoice carried the correct rate from the original RFQ in Construction. The math on each bill was accurate. The problem was not the rates. It was the quantity. Across eleven billing cycles, the vendor had billed for quantities that averaged four to six percent higher than what GRN records showed had actually been delivered. In some cycles there were no GRN records at all because the site supervisor had signed delivery notes without a formal receiving process.

The RFQ process worked exactly as intended. Everything that happened between PO issuance and final payment did not.

What a Construction RFQ Actually Controls and What It Does Not?

Before you buy something, you need a RFQ in Construction. The goal is to make it possible to fairly compare vendors for a specific service or material need. If written well, it spells out the requirements the vendor must meet, the amounts being bought, the time and place of delivery, the payment options available, and the criteria that will be used to choose the best vendor.

The agreement is what an RFQ controls. It establishes what rate will be paid, what the specification will be, and what the terms of the deal are. A vendor who quotes on a well-written RFQ and then gets a purchase order has entered into a written business agreement that spells out all the important terms of the purchase.

An RFQ doesn’t cover anything that happens after the PO is sent out.

The RFQ rate is set in stone. There is a record of the agreed-upon specification. But when the goods are received on site, it is checked to see if the amount delivered matches the amount ordered. During the processing of an invoice, it is checked to see if the billed quantity matches the delivered quantity. When you compare an invoice to the original PO, you can see if a rate change has slipped into the next billing cycle. At the RFQ stage, none of these decisions are made. Weeks or months later, at delivery and billing, they happen. Most Indian construction companies do these things by hand, without a structured way to check them.

The RFQ is the first step in controlling procurement. It’s also where most construction companies end.

The Four Points in Construction Procurement Where Overbilling Actually Occurs

Vendor overbilling in construction does not happen during the RFQ process. It happens at four specific points after the PO is issued, through mechanisms that are invisible to the procurement team unless someone is actively looking for them.

Quantity inflation at delivery

A supplier brings 460 bags of cement to a building site. The driver of the delivery truck shows a delivery note that says there are 500 bags. The site supervisor is in charge of three other things at the same time, doesn’t say anything, and signs the delivery note. The vendor charges for 500 bags at the agreed-upon RFQ rate. The payment system sees the 40-bag quantity gap as a valid transaction because the signed delivery note shows 500 and the invoice charges for 500.

There is no problem with the rate. The rate for the RFQ is right. The RFQ in Construction process doesn’t have a way to fix the delivery verification problem.

Rate creep across billing cycles

The original PO specifies steel at Rs 58,500 per metric tonne. The first three invoices arrive at exactly that rate and are approved without scrutiny. The fourth invoice arrives at Rs 59,800 per metric tonne with a note referencing market escalation. Nobody formally approved the rate change. The difference is Rs 1,300 per tonne. On a 15-tonne delivery it adds Rs 19,500 to the bill. Across a project with 200 tonnes of steel across multiple deliveries, unapproved rate escalations accumulate into lakhs of unbudgeted expenditure.

The RFQ locked the rate at the time of vendor selection. Nothing in the standard manual invoice approval process verifies that the locked rate has held across every subsequent billing cycle.

Billing for partial or undelivered material

A vendor delivers part of an order and says they can’t deliver the rest for logistical reasons. They promise to deliver the rest within a week. The vendor sends an invoice for the full amount of the purchase order, not just the amount that was delivered. They also say that the balance is still due. The accounts team agrees to pay the full invoice because they think the balance delivery will happen soon. The balance never comes in full. No one follows up in a systematic way. Across all projects, there are still problems with partial deliveries that were charged at full PO quantities.

This pattern is very common in Indian construction, where vendors don’t have formal contracts and partial delivery followed by full billing is seen as a way to manage cash flow instead of an overbilling event.

Duplicate billing across invoice cycles

A vendor submits an invoice for a delivery made in week four. The invoice is processed and payment is approved. In week nine, a slightly modified version of the same invoice arrives with a different invoice number and a date one day earlier than the original. Manual invoice processing systems with no duplicate detection logic compare the new invoice against the PO, find the amount matches a legitimate delivery, and approve the second payment.

Duplicate billing is the most structurally preventable of the four mechanisms and the one most frequently missed by manual procurement systems operating at high invoice volumes across multiple concurrent projects.

Why Your RFQ Process Has No Visibility Into Any of These Problems?

One thing unites all four of the overbilling strategies mentioned above: none of them take place during the RFQ in Construction or PO stage. They can happen during delivery, during billing, or over the course of several billing cycles. Despite its rigorous nature, the RFQ process cannot see inside any of them.

The majority of building procurement teams focus their control efforts on choosing vendors. The specifications are written with care. A number of vendors are contrasted. Rates are discussed and agreed upon. Documented terms are attached to the PO. The procurement team now considers the task completed.

The three processes that come after a purchase order is issued, delivery verification, invoice matching, and payment authorization, are where the real financial risk in construction procurement is concentrated. All three of these processes are carried out manually in Indian MSME construction firms that oversee several ongoing projects using paper delivery notes, email invoicing, and Excel-based payment monitoring.

At these three stages, manual systems are not control mechanisms. These are procedures that give the impression of control while architecturally hiding the four overbilling mechanisms. In a system without a formal recounting requirement, a site supervisor who writes a delivery note without recounting is not being careless. In a system lacking a GRN comparison requirement, an accounts manager who approves an invoice against a paper PO without cross-referencing a GRN is not committing a mistake.

Vendor dishonesty is not the main cause of the overbilling that builds up across a building project through these techniques. It is brought on by procurement processes that do not require verification at the locations where overbilling takes place. Verification requirements that were never developed by the procurement system cannot be retroactively imposed at the delivery and billing stages by the RFQ.

What Three-Way Matching Is and Why Construction Procurement Cannot Work Without It

The activity of comparing three documents before any vendor payment is authorized is truly matched. It contains the original PO showcasing agreed quantities and rate, the GRN recording what actually was delivered to the site, and a vendor invoice for claiming payment for delivered goods and services.

These three documents need to match on quantities, rates, and specifications for payment to finally proceed through the approval workflow. If any of this document is incorrect or disagree with the other, the invoice can be held pending. It puts a break on approval until the mismatch is explained and the documentation is correctly justified.

System is a standard practice in retail and enterprise procurement, but in small Indian MSME construction company, there is no sign of it. It is not because of the lack of knowledge. The reason is the struggle of having a three-way matching structure system where three documents exist simultaneously in a system capable of comparing them automatically. Manual construction procurement system cannot meet this requirement.

There is a file for paper purchase orders. Site supervisors sign delivery notes and either keep them on site or send them to the office days later. We get vendor invoices by email or WhatsApp, and then we send them to accounts to be processed. There are three copies of these three documents in three different places and three different formats. People only compare them by hand when they choose to, which doesn’t happen consistently in environments with a lot of procurement.

The four overbilling mechanisms described earlier are all caught by properly implemented three-way matching. When the GRN quantity doesn’t match the invoice quantity, it means that the quantity has gone up at delivery. Rate creep happens when the rate on the invoice doesn’t match the rate on the purchase order. When the GRN quantity is less than the invoice quantity, partial delivery billing is caught. When an invoice matches a PO and GRN combination that has already been processed, duplicate billing is caught.

Three-way matching does not stop vendors from trying to overcharge. It stops them before they can make a payment.

Why GRN Is the Weakest Link in Indian Construction Procurement?

Without the accurate goods receipt note, the three-way matching is left with only two documents to compare, but the most important one that keeps the record of what actually arrived is missing.

In Indian construction, the GRN is the weakest document in the procurement chain for three reasons.

First, there is no existence of written construction projects at all. There are multiple construction sites that operate without any formal receiving process. The materials are arriving at the site, the driver is presenting a delivery challan, a supervisor is signing it, and the challan stays in the pile. There is no formal GRN that has been raised against the purchase order because nobody feels the requirement of it.

Second, if the GRN is created in an Indian construction project, it is often created retrospectively. If the delivery is happening on Monday, the GRN is generated into a system that company uses on Wednesday, totally on the basis of the recollection of supervisors’ memory. The quantity of material recorded after two days solely on the basis of memory are not quantities that were verified at the moment.

Third, the accuracy of GRN completely depends on whether the person who is creating it is physically counting or measuring the delivered goods against PO specification. Any supervisor who is accepting the quantity on the basis of the driver’s statement and without any verification by creating GRN, is not the actual quantity, it is assumed one.

An inaccurate GRN does not protect against overbilling. It codifies the overbilling. If a driver says that he’s delivering 500 bags, the supervisor trusts blindly, and the GRN has record of 500 bags, this three-way matching will approve an invoice for 500 bags because all of the three documents agree now. They all agree on the wrong number, but the matching process has no way to know that.

Creating GRNs that actually verify what was delivered requires: a formal receipting process where someone is responsible for counting or measuring at the point of receipt, recording at the time of delivery not retrospectively, and connection to the PO so the receiving team knows exactly what quantity is expected and can identify any shortfall immediately rather than after the delivery truck has left the site.

What Procurement Control Actually Requires Beyond the RFQ?

There is a connected six-step chain where each step creates a verified record that the next step requires. A construction procurement system that helps you avoid the four overbilling mechanisms is not built around better RFQ in Construction. These are the steps that you need to learn.

Step 1: BOQ-linked material requisitions

The process of procurement starts when there is a rise in need of material at the site. When a team raises material requirements, it should be linked to a specific BOQ line item and project budget allocation. This step helps in the smooth procurement process that is connected to the project scope from the very beginning and the quantities that have been procured reflect directly to the actual project requirements rather than the estimated or informal requests.

Step 2: Structured RFQ with documented vendor comparison

Multiple vendors quote on identical specifications with rates, delivery terms, and conditions recorded in a comparable format. Vendor selection is documented with the reason for selection visible alongside the comparative quote data. This is the step most Indian construction companies already manage reasonably well.

Step 3: Purchase order with locked quantities and rates

A purchase order is issued with specified quantities and rates, which eventually becomes the reference document for everything that follows. After PO is issued, rate and quantity change and it requires a formal amendment with approval rather than an informal negotiation between vendor and site team.

Step 4: GRN at the point of delivery

When material arrives at the site, a person is responsible for accurate counting or measurements. At this stage, delivered quantities are verified against purchase order. The GRN is created at the time of delivery, records whatever was actually received against order quantities, and flags any shortfall immediately before the delivery vehicle leaves the site.

Step 5: Automated three-way matching before invoice approval

Any vendor invoice is compared against the PO and the GRN before getting any approval. Discrepancies between invoice quantities and GRN quantities or between invoice rates and PO rates are flagged automatically along with the specific details about it. Invoices that pass the matching procedure are ready for approval. Invoices that fail matching are held pending resolution.

Step 6: Multi-level approval with budget visibility

Payment approvals are routed through a defined hierarchy with project budget remaining visible at the point of approval. Approvers see not just whether the invoice is accurate but whether approving it keeps the project within its procurement budget allocation.

Step 2 is the RFQ. It is important and useful. But it works on its own, separate from Steps 4 and 5 in most Indian construction procurement systems. Overbilling happens when there is a difference between what was agreed upon in the RFQ, what was actually delivered on site, and what the vendor is charging.

Why Manual Procurement Systems Cannot Maintain Control Past the Purchase Order?

The six steps that have been mentioned above are not complicated. Every construction procurement professional that is going through this article will see that each step is something that is necessary. The challenge is not understanding the chain. It is running all six steps at the procurement volumes a growing construction company generates across multiple concurrent projects. If a contractor is managing multiple projects simultaneously, he may process 40 to 60 vendor invoices per month across materials, subcontractors, and equipment. Doing the manual work and allocating each document, each invoice, like the original PO, the GRN from the site, and vendor invoice, as well as comparing them line-by-line for quantity and rate accuracy and identifying discrepancy before authorization can be a difficult task. It needs a dedicated procurement staff having a full-time document management operation.

In real life, this doesn’t happen. In most Indian construction companies, an accounts team member checks that the invoice amount seems fair based on the project’s recent purchases and then sends it to a manager for approval. Sometimes, the PO is checked. The GRN isn’t checked very often because it might not be in a format that is easy to find. There is no systematic way to do three-way matching.

This is not a failure of the procurement team. It is a structural limitation of manual procurement systems operating at volumes and complexity levels for which they were not designed.

Software or platform that connects RFQ, PO, GRN, and vendor billing in one singular system can easily perform three-way matching automatically at every invoice across every project simultaneously. The system does the comparison in seconds, before any human reviewer sees the invoice. It would take a procurement team member fifteen to twenty minutes to do it by hand for each invoice.

How Connected Procurement Software Closes the Gap Between RFQ and Payment?

The fundamental requirement for catching vendor overbilling systematically is having the purchase order, the goods receipt note, and the vendor invoice in the same system simultaneously so comparison can happen automatically rather than manually.

Site teams directly record received amounts against the pertinent PO line items when they produce GRN entries at the time of delivery via a linked system. After then, the delivery record remains in the same location as the first order. In order to detect discrepancies early, the system verifies an invoice raised by the vendor against both the PO and the GRN before submitting it for approval.

Discrepancies surface as specific flags: this invoice claims 500 units but the GRN for this PO records 460 units delivered. This invoice rate is Rs 59,800 but the PO rate is Rs 58,500. This invoice reference number matches an invoice that was processed and paid in a previous billing cycle. Approvers see these flags before authorization rather than after payment, which is the only point at which they can make a difference.

There are different platforms out there like Onsite that helps in connecting RFQ, purchase order, GRN and vendor billing in one singular construction-specific procurement workflow, running three-way matching automatically at every invoice cycle across multiple projects simultaneously. It eliminates the work for procurement managers to manually reconcile invoices and helps in avoiding errors.

The overbilling that currently passes through manual systems undetected does not require vendors to be dishonest. It is in the requirement of a gap between what was ordered, what was delivered and what was billed to remain invisible to the people authorizing payment. A system of procurement that is connected makes the gap easily visible before payment is authorized rather than during cost review six months later.

What to Do Differently Starting From Your Next RFQ?

The RFQ process does not need to change. A well-written construction RFQ that achieves comparable vendor quotes and documents the basis for vendor selection is doing its job correctly.

What needs to change is what happens after the PO is issued.

Three practical actions that close the gap between RFQ-stage control and payment-stage control in construction procurement:

• Make GRN creation compulsory at the time of delivery, not after. No material should be accepted unless a GRN is recorded during receipt by someone who has physically checked the quantity against the PO. This one step prevents quantity inflation at the source, before it moves into billing and becomes difficult to correct.
• Build three-way matching into your invoice approval workflow. Before any vendor invoice is routed to an approver, require that it be compared against the PO and GRN for quantity and rate accuracy. In a manual system this means making the comparison a formal step with a sign-off requirement. In a connected system it happens automatically.
• Link each purchase order to the project’s budget. Every time you commit to buying something, the budget for that material category should go down right away. When an approver can see that approving a vendor payment will cost more than the project’s budget, budget discipline becomes a normal part of procurement authorization instead of something that has to be done every month.

You don’t have to spend a lot of money to make these three changes. They need to be disciplined in how they do things, and as a growing construction company buys more and more, they need a connected platform that makes discipline a regular part of the process instead of relying on individual vigilance.

The RFQ Protects the Rate. The Rest of the System Protects the Budget.

The right way to start controlling procurement is with a well-written construction RFQ. It sets the price, describes the requirements, and explains why a vendor was chosen. These are really important things to get right.

But the losses that eat into construction project margins through procurement aren’t mostly rate losses. They are losses in quantity, billing cycles, and verification that happen at times when the RFQ in Construction was never meant to happen.

It’s not always true that contractors who always protect procurement budgets are writing better RFQs than their competitors. They are checking deliveries more carefully, matching invoices more systematically, and linking procurement commitments to project budgets in real time so that overruns can be seen before they get worse.

The RFQ is what leads to the purchase order. To avoid losing money that could have been avoided, the rest of the chain must work with the same level of care from the purchase order to the final payment. Most construction companies put a lot of money into getting the RFQ right, but very little into getting the delivery-to-payment chain right. That’s where procurement budgets quietly go away.

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