Incrementally making a Racial Trait replaced?

[TCArknight]

I have a racial ability Z which has 3 uses per day. I have Alternate Racial Traits X and Y which remove 1 and 2 uses of Z respectively. I have the script below on X and Y

@ Levels/1001

field[abValue].value += 1

~Subtract uses from trkMax for Burst
hero.child[Z].field[trkMax].value -= field[abValue].value

if (hero.child[Z].field[trkMax].value <= 0) then
  perform hero.assign[AbReplace.Z]
  perform hero.child[Z].assign[AbModify.Z]
  perform hero.child[Z].assign[AbReplace.Z]
  perform hero.child[Z].assign[RaReplace.Z]
  perform hero.child[Z].assign[Helper.Exhausted]
  perform hero.child[Z].assign[Helper.SpcDisable]
  perform hero.child[Z].assign[Helper.SpcReplace]
  endif

and I have a prereq on each

tagcount[AbReplace.raXeBurst] = 0

to account for other traits completely replacing Z. If I add both X and Y to the hero, Z does show as disabled/replaced, but then X and Y show the pre-req error.

Is there a better way to handle this situation?