I currently take a Mitochondrial cocktail, which consists of high doses of vitamins. I will check my B12 to see if is the methyl variety. The weekly shot is cyanocobalomin, I have read about the possibility you mentioned of difficulty in using and storing this form of B12.
My liver checks out fine, only elevation is Alk Phos which hovers at 145. the other transaminases have been normal, liver CT normal. Alk Phos is a bone marker as well, which I have periods of joint and long bone pain, but further test have not been indicative of any bone issues.

Thanks,
Camelot