Just like the others entioned; the transformation is not really worth it
The only reason for transformation is just as a breeding grounds alternative with lower initial power cost (90% of the original unit's power flows into the void and the transformed unit e.g. abomination would only bind 165 power instead of 220, would then return 90% of the 165 into void). For your t4 either transform your creepers or just use a breeding ground, sunken temple is not worth it as transforming uses charges.
Beware, when transforming they will stay at the same percentage of health, meaning tran