Dear Venu
as you are aware business will create debit memo in case of of less pricing.
Let us take one scenario--the actual cost is 10Rs but you priced only 9Rs on 10th of April in your bill--so debit memo can be raised--at this junction you applied reason for rejection with OLI active..
But government has ordered business(or management has taken a decision)to increase the price from 1st of April to 11Rs..So need to raise one more debit memo will be allowed in this case..
Hope this helps..
Phanikumar