SLA customization in PA

Dear Experts,

How to customize SLA to pick same original charge account for any adjustments (like Transfer from Indirect project to a Contract project) made for the expenditures for all sources?

We mainly use

These sources:

1) Oracle payables supplier invoices

2) Oracle payables supplier invoices exchange variances

3) Inventory Misc

4) Migrated costs some years ago from custom source as accounted transactions.

Any document if have will be helpful for setups.

We cant use default implementation options setup.

Thanks

Venkat