UBL Invoices
Invoices created with onFact can be exported to the universal UBL.BE and E-FFF formats, readable by virtually any accounting software. That way you don't have to enter anything twice and onFact invoices can easily be imported into the accounts.
onFact's 'Purchase invoices' module can itself automatically process UBL invoices, which again saves manual entry. All purchase invoices can also be exported to a UBL format for automatic processing in the accounts.