I have a subk, who in their MSP schedule, insist on using the latest contract modification award dates to drive recurring quarterly tasks rather than using the original contract award date. Those mods neither address nor pertain to the quarterly tasks, so my belief is the original project award date should be used to drive those quarterly tasks. This leads to disparate contract deliverable dates. It also fouls the baseline by continually changing the award date.
I cannot find any documentation providing guidance or best practice on which date to use, so I am hoping for some assistance from a PMISP or other scheduling SME.