If DP's theory is correct, I wonder if it is really ever advisable to even be taking a high dose B-complex due to B-2's low absorption compared to the other B's and B-2 stores being used up to help assimilate the massive amounts of other B's. Maybe if you even gave yourself extra B-2 to compensate along with a B-complex you still might not be doing yourself any favors because maybe you will just urinate out the additional B-2 because of it's low absorption, although I would like DP's thoughts on if one were to take a B-complex if additional B-2 can be taken sublingually to overcome the absorption issue. Maybe still it is just too much overkill on the mg content of the other B's? If so, maybe one could just cut way back on their daily dose of B-complex <maybe 1/5th or even 1/10th of a pill? I don't know..just guessing>. Even if you bought a low mg content B-complex, most of those have the dreaded "folic acid" in them. I atleast know one thing about myself, I feel worse taking a high dose B-complex.
I take most of my vitamins seperately. That way I know what might be doing what. B6 makes me feel terrible and I can not tolerate.
To dog person:
In my experience while doing methylation, one vitamin or mineral as a co-factor can make a difference.
I hope you are on to something in the bigger overall picture.
Edit: I want to add my standard disclaimer: I think everybody is different and will respond differently to different treatments. probably No silver bullet for everybody... :O)