Two things:
1) If the unit is over shooting in the up only, and your transition is ok, I would believe based on your report, the selector IS seeing the slowdown magnets. LU is the question.
Visual inspection such as Dirt suggested would be helpful. IIRC, all magnet inputs can be seen from cartop.
2) Aren't there LED's for UL and DL on the selector head pc board? Verify these on cartop inspect. Does it level in properly to the top floor?
If it IS slowing, just blowing through the floors, maybe the up leveling adjuster is loose on the Maxton valve or just the UL adjustment (just thinking out loud here).
By chance do you know if the access up speed seems normal like 10fpm or so? That would give you a good visual on the true UL speed. Could very well be the selector head itself, but we don't want to jump there yet.
