Working with finance teams across Korea, we see the same rematch surprises repeat—not because people are careless, but because operational apps and ledgers optimize for different jobs. Here are gaps that show up often in SME stacks.
VAT rounding that never matches on purpose
Marketplace or POS apps may round VAT per line; the ledger may round per document. The difference is tiny per invoice and loud in aggregate. Tag it as a known rounding class with a monthly tolerance, or you will “investigate” the same few thousand won forever.
Holiday cutoffs nobody wrote down
Chuseok and Seollal stretch warehouse and bank calendars. An app may accept “complete” on a holiday eve while the ledger’s posting calendar skips until the next business day. If your sync validation ignores public holidays, your exception board will spike twice a year for non-issues.
Marketplace fee timing
Fees often settle days after the sale event that hit revenue. Teams that reconcile sales and fees in one pass create artificial breaks. Split the assertions: sale completeness first, fee completeness on the settlement calendar second.
Multi-warehouse inventory feeds
When each warehouse app exports stock movements with local clocks, consolidated ledger postings can look incomplete. Require a warehouse ID on every export row and reconcile by site before you reconcile the company total.
If these patterns sound familiar, the App-to-Ledger Validation Guide pairs well with a short Field Check engagement.