Massive doses of methylfolate are used to try and treat some depressions. It is not working out as they planned however.
Some people get agitated on high dose folate.

Also there is a situation of very high dose folic acid in young women increasing the rate of colon cancer. This is thought to be due to pre-cancerous lesions gobbling up the folate and that is stimulating growth. But no one knows for sure yet. Some young women take 5mg or more of folic acid before and during pregnancy, especially if they have had a child with neural tube defects already. Because colon cancer is not common in this age group it is a concern, but not proven yet.

Metanx (just because is RX) is not really approved for efficacy by the FDA. It is under an umbrella called "Medical Food". It is only RX because it contains more than 1mg of folic acid and there is a rule that anything over 1mg requires RX in US. But studies were not needed for its status for releasing to the American Public.

I don't think the short course of samples is a concern, but if you get agitated with that high folate, you could just take one instead of two a day.
I prefer this product because it is enteric coated. P5P is not stable in stomach acid:
http://www.iherb.com/Now-Foods-P-5-P...60-Tablets/740
One of these a day, is plenty.
B2 is included because it is the cofactor for pyridoxal kinase to convert B6 to P5P... that is why it is in there. The enzyme works on other B6 present in your foods.