Hi Suresh,
Here is what I understood.
MRP Group Parameters are "Setting from Plant Parameters" (i.e initial)
Plant Parameters are "BOM explosion number/order start date"
Date on BOM explosion number "21.12.2300"
In this case, MRP Group parameters redirects system to run based on OPPQ settings. As per that, system will look for date from the BOM explosion number if one exists; otherwise the order start date. The BOM explosion number date is 21.12.2300 and system should pick that in production order.
Pls check for "BOM expl. no. for MTO production" indicator in plant parameters (OPPQ). If this indicator is selected, then system will ignore BOM explosion number for Make-to-stock scenarios and explode BOM as per config settings. This happens if your finished product has MTS relevant strategy in MRP 3 view.
If you are testing this scenarios then make sure you run MRP with "Planning mode 3" after changes in Master Data or config in order to check the exact results.
Do let us know your results.
Thanks,
Rohit