Quantity reconciliation / Single unit basis
Account for the whole lot.
The starting values are a fictional example. Keep physical identity and origin review separate from this arithmetic check.
0 pieces unaccounted
Unaccounted = starting quantity − sum of recorded movements. Do not add an unexplained adjustment solely to force a zero difference. Balance is checked against the exact decimals entered, without a rounding tolerance. No unit conversion or production-yield assumption is performed.
Reconcile a shipment without filling the gaps with assumptions
A provenance record connects a received lot to the documents that describe it. Matching a species name is only one check. Supplier references, quantities, shipment identifiers and the scope of each statement must refer to the material actually received.
Follow the identifiers through the record
Compare the purchase reference, invoice, shipment or lot identifier and receiving record. Preserve the original wording where names differ. An abbreviated description may be explainable, but the explanation should come from an identifiable source.
Keep quantity and claim questions separate
A quantity reconciliation can be complete while origin documentation remains unresolved. Likewise, a certificate or declaration does not explain a shortage. Assign each discrepancy its own question and retain the response with the relevant document.
Example: a split delivery
One invoice covers a purchase delivered in two lots. Record both receipts against that invoice and identify which supporting documents apply to each lot. Do not count the invoice quantity twice, or assume that a document supplied with the first delivery automatically covers the second.