Mseth,
Dont' know how helpful these will be. You can also post your question on their forum and see what response you get. Understanding hyper/hypo methylation at the gene level is still in its early stages. From what I understand, you can have both hypo and hyper occurring at the DNA level simultaneously. I'm not sure that it's about having too much of folate/B12, but more about where the breakdown is occurring in the DNA/RNA methylation patterns.
http://mthfr.net/methylfolate-side-effects/2012/03/01/
http://mthfr.net/how-much-methylfola...ke/2012/03/22/
It's really not as easy as one would think to figure this out. For us, I focused on making sure to add in B12 first, then the methyl folate, and then a B complex. Of course John is in a partial stable remission and really has no symptoms associated with MTHFR problems. But he's been at this, on some level, for the past 9 years.
Here's an article, just in case you need something to put you to sleep, on Caner and methylation. It sent my head spinning.
http://jco.ascopubs.org/content/22/2...ull.pdf%20html