Convert from 2 digits to 4 digits after decimal

We have a peculiar condition where few of the POs & SOs need to be either 3 or 4 digits after decimal from current 2.

I have attached a document which i used to do the setups & test.

Now Finance has come back saying its fine to have 4 digits after decimal in PO & OM module but it should send only 2 digits after decimal to AR/AP. How is this possible ? In short for PO & OM rounding should be 4 & AP/AR should be 2.

One of the example here is that we use Consignment Inv and the Pay-on Receipt Autoinvoice created after consumption advice had 4 digits.