Start with the evidence
Capture the original reference exactly and compare it across relevant sources. Preserve leading zeros and distinguish a transaction reference from a customer or batch identifier.
Work through the example
Payment P-00813 and invoice EX-813 share digits but are different identifiers. A remittance note linking them is stronger evidence than the resemblance of their numbers.
Make the next step clear
Keep the linking evidence with the record and explain any shortened or transformed reference. If no reliable link exists, leave the match open rather than treating the similar number as confirmation.
Keep the source context
Use confirmed source records and keep their dates, references and currencies visible. A payment request is not a receipt, a provider status is not necessarily a bank entry, and a net settlement may combine several components.