Creemator/Acorn driver sensitivity?

I have a recently acquired Creemator with the Acorn 1.3 driver and it is a pretty amazing little light. However, I've noticed that it is finicky about clicky bodies. On the VG FB1 body it came with it works fine but there is a very slight waiver in output just before the microswitch latches and unlatches. I tried it on my E1L body and it was quite erratic, switched it to the E2L and it worked flawlessly and worked flawlessly on the E1L body with the Z57 from the E2L.

Given the erratic reports of the FB1 switches, and Z57s for that matter, I wrote it up to the switches.

What is odd, however, is that the FB1 and the E1L both work just fine with either the KX1 stock head on a primary, or the KX2 head with an RCR123.

I'm not overly bothered other than having to make sure I switch tailcaps when I move the Creemator to either the E1 or E2 body - which is marginally a pain. I'm inclined to call Surefire and get a replacement Z57 regardless, but I was curious if anyone else had issues with their Acorn based lights being more sensitive to even small fluctuations in the current, and if perhaps I should switch to AWs IMR cells (currently using AW protected black 750ma cells that are 1+ years old and have been used regularly through my Novatac 120P).