If it works where, after you modify (even to a different ride), you become eligible for a new LL 2 hours after you made the ORIGINAL selection (not the modified selection) or when you tap in (whichever is earlier), that would be huge!!
Even on old Maxpass, which I believe had a sort of modify, your 90 minute window got reset if you changed. So I often faced a dilemma where I thought I’d like to modify, but I don’t want to reset my 90 min window, particularly on very crowded days.
We’ll see exactly how it work, my guess is the 2 hour window will reset to when you modify, not the original selection.