Hello,
Are you using DIMP IS mill solutions?
Please check these OSS notes
439349 - MILL: Default quantity confirmation
708994 - Mill: incorrect default quantity with confirmation
Also note for production order, the functionality of proposed quantity for operations getting adjusted to the confirmed yield quantity of predecessor operations is available as standard.
In transaction code OPKP for maintaining production scheduling profile, for certain combination of plant and profile, in the confirmation section there is a flag:
"Adjust Quantities in Order to Actual Values".
Also in OPK4 confirmation parameter you can define the Overdelivery tolerance setting.
Best Regards,
R.Brahmankar