This calt isn't working...

Sorry to ask so many questions here… I’m trying to apply a calt so that when a triple-stack of numbers is followed by a hyphenminus, the hyphenminus transformed to a dash that is center-aligned on the bottom number (here, it should be the 3):

I can’t figure out for the life of me what’s wrong. I checked to make sure the 753 stack is part of the correct class:

Have I set up my calt incorrectly? Everything else I’ve tried has worked as expected.

Update: Thanks to Erwin, I got it figured out! I had my lookups in the wrong sequence order.