Hi,
Can you try in debugging by passing CH_X_LF_CALCTYPE = B (Carryout new pricing) in
BADI ME_DEFINE_CALCTYPE
Method: DEFINE_CALCTYPE
so that in ECC PO price will be redetermined from contract.
If its work, then implement a BADI by put a condition on SRM document type.
Regards,
Rakesh Naragoni