The requirement for a revised Accepted Programme is typically every four weeks, so what I have suggested previously is at that point in time taking a snap shot of that programme at the time/date agreed, and extract an XER file (this is the Primavera file) and also a PDF version of the programme at that point that can then be issued for acceptance.
You do still need to maintain this process otherwise you will never be able to (contractually correctly) be assessing compensation events.
You do still need to maintain this process otherwise you will never be able to (contractually correctly) be assessing compensation events.