In many companies, account assignment rules live in two places: in the head of the most experienced accountant and in an Excel list nobody fully understands anymore. Automation then fails not on technology but on the fact that the rules are not formalized anywhere.
A Buchungsmatrix (a posting matrix) changes that. Posting rules are stored as a configurable table that derives the correct account from the attributes of a document: traceable, testable and adjustable without programming. I gather these rules with your accounting team, translate them into the matrix and test them against real data.
Four dimensions, one account
The matrix documented in the invoicing whitepaper works with four dimensions: recipient country × invoice type × tax rate × cost type determine the account. A domestic invoice at the standard tax rate is assigned differently from an intra-EU service, a down payment differently from a final invoice, without anyone having to keep the cases in their head. Because invoice type is its own dimension, the matrix also covers the special cases of down payments, installments and cancellations.
Combined with the DATEV integration, the matrix is applied when the posting batch is created: outgoing invoices are exported in real time, and the account assignment happens in the same step as the invoice.
AI pre-assignment with review and approval
On the inbound side, AI-assisted pre-assignment complements the matrix: posting suggestions based on historical booking data, reviewed and approved by your accounting team. Deliberately not an autopilot: every automated assignment has to remain traceable, otherwise errors compound in the archive. Why misassigned cost centers get expensive in particular is covered in my article on cost centers in DATEV.
From rulebook to daily operation
Getting there is process work: gather the rules with accounting, make the edge cases explicit, translate them into the matrix, test against real data and only then go live. The implemented logic is openly documented in both whitepapers. How account assignment fits into the full path from document to posting batch is shown on the E-Invoicing & DATEV overview.