I think it’s simple? You break the old barrier, by continuing - just needs to be 5-10 seconds - to push > TP after you pulled MPA down.
Your HIE will increase as you continue to push above MPA/TP, but it is volatile and difficult to calculate, but MPA is individual, determined by PP.
Anyway, they have good experts - and lots of documentation - to explain the science a lot better than I would be able to 