Hm.
You know, Variable Abilities and Limitation don't work together as smoothly as I would like.
Because when you attach Limitation to Variable Abilities, you attach it to the entire pool. But Limitations like this one don't actually shut down the entire pool, they just shut down the ability to re-allocate it.
If the Powers were better-written, you could just attach Limitation to the Refresh tax you pay to make your abilities variable.
So I recommend just pretending it works that way. Reduce the extra Refresh cost of Variable Abilities by half or so. If you've got 12 form points and a 3 Refresh surcharge, maybe you pay 13 Refresh instead of 15.
PS: How far are you in Worm?