MTHFR C667T: Should I supplement? Plus B6 is always high...

[DarkRiver]

I found out recently that I have the MTHFR mutation. My report says: "This individual is heterozygous for the C677T polymorphism in the MTHFR gene." Apparently, being heterozygous is not as bad as being homozygous.

The standard recommended course of action for this mutation is to supplement with folic acid, folinic acid, or folate (supposedly the latter two are preferable).
However, during the past year I have had my B12 and folate levels checked and they have been good:

Vitamin B12, 638 PG/ML (180-914), March 2016

Vitamin B12, 801 PG/ML (200-1100), May 2017

Folate, 15.9 NG/ML (>4.0), March 2016

Folate, 17.0 NG/ML (>5.4), May 2017

What's odd is that despite only occasionally taking a multivitamin, my Vitamin B6 levels keep coming back high:

Vitamin B6, 47.6 NG/ML (2.1 - 21.7), July 2016 - High

Vitamin B6, 27.8 NG/ML (2.1 - 21.7), May 2017 - High

So my questions based on the above are:

1. Should I still take a daily or frequent B12+folate supplement? The one I have contains "folate (as Metafolin®, L-5-MTHF) 800 mcg, and vitamin B12 (as methylcobalamin) 800 mcg".

2. Should I not take my multivitamin anymore to help bring down my B6 level? The vitamin which I take 2-3 times weekly contains 4.16 mg of B6 as pyridoxine HCI, or 208% of the daily recommended value. Should I switch to pyridoxal-5-phospate (activated B6) instead?

My primary symptoms are depression, brain fog and cognitive impairment. Searches on Pub Med have found some links between MTHFR C677T and depression. Thanks so much for any advice you can provide.