PO Open Interface and account generation

We are testing import of PO's via PO Open Interface.  We also have Grants Management installed. When importing a PO via the open interface the correct GL expense account (variance, etc) is not being generated as compared to a PO entered via the application screen. In short, the open interface appears to run a default account generation workflow.

How do we get po open interface to use the same account generation as does the PO application form?