Currently there is no functionality within Finance to use posting definitions with AP Invoice journals. When you go to Transaction posting definitions under Accounts Payable there is only the option for Vendor invoice which is based on purchase orders.

This limits the use of AP invoice journals if you have Fund or any other balanced dimension in use as you cannot break an AP invoice expense out by dimension as it will not balance. The only way to have this work without posting definitions is allowing duplicate AP invoice numbers and creating a separate liability for each expense line for an invoice. This creates a messy AP aging as you need to add them all together for the exact invoice.

The ask is to add a posting transaction definition for AP Invoice journal as well as purchase invoices