Consideration exchanges over separate contracts with same contractor

We have a contractor that has multiple awards off of our MACC IDIQ. For this scenario we will just treat them as having two contracts and call them Contract A and Contract B. For Contract A the contractor is requesting a Period of Performance extension without having any excusable delays. In lieu of implementing Liquidated Damages, we were considering requesting consideration on Contract B to add a small amount of extra work for no cost to the government. What is the precedent for this and is it allowed?