By Vaibhav Rane, Founder, Cresolv One
This is part of our GST & TDS Reconciliation Automation Guide.
A standard 3-way match — comparing the invoice against the PO and the GRN — verifies quantity, price, and that goods were actually received. What it never checks is whether the GST registrations involved in the transaction actually align. For a business operating under a single GSTIN, that's rarely an issue. For a conglomerate with multiple state registrations under one PAN, it's a real and easily missed exposure.
When a business has GST registrations in several states — because it has warehouses, branches, or operations in each — every purchase transaction has three GSTIN touchpoints that all need to agree: which entity placed the order, which entity the vendor is invoicing, and which GSTIN the purchase order was actually raised under. A standard match checks whether the goods and pricing are correct. It doesn't check whether these three GSTINs are consistent with each other, which means a transaction can pass every normal check and still be filed under the wrong registration entirely.
The common failure pattern: a purchase order is raised correctly against one state's GSTIN, but the vendor's invoice — through a data entry error, an outdated vendor master record, or simple confusion between similarly-named branch entities — lands against a different GSTIN's books. Every quantity and price figure matches perfectly. The invoice still gets approved and paid. The problem surfaces later, if it surfaces at all: input tax credit claimed under the wrong GSTIN isn't valid credit for that registration, regardless of how correct every other number was.
Extending the standard match to seven points closes this gap: ordering GSTIN (which entity placed the order), vendor GSTIN (which entity the vendor is actually registered as), and PO GSTIN (which registration the purchase order itself was raised under) — checked for alignment — alongside the standard GRN quantity, rate, and QTY verification against the PO, plus a dedicated tax verification step confirming the GST treatment itself is correct for that transaction. The three GSTIN checks are what a standard 3-way match structurally can't catch, because it was never designed to look at registration-level alignment at all.
Say your Maharashtra entity places a PO with a vendor, but that vendor's invoice references your Gujarat entity's GSTIN — perhaps because the vendor's system defaulted to a previously-used branch record. Quantity matches. Price matches. GRN matches. A 3-way match approves it without hesitation. A 7-way match flags it immediately, because the ordering GSTIN (Maharashtra) doesn't align with the vendor's invoiced GSTIN (Gujarat) — a mismatch that has real ITC consequences if it isn't caught before the invoice posts.
The more states you operate in, the more these three-way GSTIN combinations exist, and the more a purely quantity-and-price-focused matching process leaves uncaught. This isn't a rare edge case for genuinely multi-GSTIN organizations — it's a structural gap that scales with the number of registrations and vendors involved, which is exactly why it needs to be a built-in check rather than something a person is expected to notice on a case-by-case basis.
Cresolv One's AP Automation runs 7-way matching as standard for multi-GSTIN entities — checking ordering GSTN, vendor GSTN, and PO GSTN alignment alongside GRN quantity, rate, QTY, and tax verification — catching the registration-level mismatches a standard 3-way match was never built to see.
If your matching process has never once flagged a GSTIN mismatch, that's usually not a sign it can't happen — it's a sign nothing is checking for it. See our AP Automation.