Hi Nitin,
While setting QM status red at PSA level, it set delta pointer at RSA7. after that once you trigger delta info pack, its ask repeat delta.
see, as your getting delta, never be chance to get huge erroneous records, because user will know the correct format which source system live form years on.
once we are on live, as my guess there won't be an issue at PSA, because psa can accept any kind of data and you may won't receive source related errors as your on live.
if expects such chance, you can use error stack after the psa and before the target. so wrong records will move stack and correct records will move to target. do the correction at error stack and load those records to target thru error dtp.
Pls refer this. maximum may clear your doubts.
Thanks