When starting a new split you should have the option to start data collection over again: Comparing your PRs when you have something at the beginning of the workout vs the end, or lower reps or higher rests etc. doesn’t make a lot of sense . It also encouraged clients to go too heavy trying to beat their old numbers when they really should be focusing on that split (if trainers what to keep them that’s also fine but I prefer to compare the PRs for this split and not all time)