It will be depend upon different business scenarios. Let me explain:
1. Create PO with price 100 and do MIRO (change amount to 103 in MIRO line item), GR Non-Valuated tick, No goods receipt.
=> There will be no price difference.
System will post accounting entry as below:
KBS - G/L account Debit (used in purchase order) 103.
KBS - Vendor Account credit 103 .
2. Create PO with price 100 and do MIRO (change amount to 103 in MIRO line item), GR Non-Valuated untick, No goods receipt.
=> There will be no price difference.
System will post accounting entry as below:
WRX - GR/IR clearing account debit 103.
KBS - Vendor Account credit 103 .
3. Create PO with price 100, post goods receipt (value 100) and do MIRO (change amount to 103 in MIRO line item or change PO price to 103), GR Non-Valuated tick.
=> There will be no price difference.
System will post accounting entry as below:
KBS- G/L account Debit (used in purchase order) 103.
KBS - Vendor Account credit 103.
4. Create PO with price 100, post goods receipt (value 100) and do MIRO (change amount to 103 in MIRO line item or change PO price to 103), GR Non-Valuated untick.
WRX - GR/IR clearing account debit 100.
KBS - G/L account Debit (used in purchase order) 3.
KBS - Vendor Account credit 103.
System doesn't need transaction key PRD at all for these above 4 scenarios.
You should test the same in your SAP system. If you have different scenario, then please explain your scenario.