Allegro Design 17.4 After revising pad stack, what is preventing me from updating the pad stack in the design?

Hello avant, have you tried refreshing the padstacks from Tools > Padstack > Refresh command?

Make sure to  enable the "reset customizable drill data" in the Refresh Padstack dialog box. Some data like Drill tolerance will not be updated if this is not selected.

I am trying to understand why this time-saving function does not work in 17.4

I am trying to understand why this time-saving function does not work in 17.4

You can try using batch commands, This can be done with the command refresh_padstack that can be run on the OS command line. 

   for %f IN (*.dra) DO refresh_padstack -d %f

I am asking about using the padstack editor to edit a padstack in a design, and then updating the design from the padstack editor.