Dear Ganeshan,
If GR is made with full qty. The account entry will be :
Inventory a/c DR 417
To GR/IR a/c CR 417
Logically the MIRO should be done with Full qty,
The account entry would be:
GR/IR a/c Dr 417
To Vendor a/c Cr 417
But you have do the MIR7(park) less qty.so system will recognise the vendor would credited less as GR/IR amount would be always same, so the diff price will be go to Consumption account through offsetting posting Transaction key GBB with General modification VBR.
the account entry would be:
GR/IR a/c Dr 417
Vendor a/c Cr 139
Consumption alc Cr 278
I hope it will clear your concept.
Regards,
Shyam