Having recently had blood level check for B-12, TSH, and D levels, I appreciate the information and discussion shared.
My recent B-12 lab results noted *
High* @
"1200" on the lab printout.
It will be interesting to see what my dr. says on Tuesday when I see her.
My primary care physician typically always comments
"Your B-12 level is too high. You can stop taking B-12 supplement."
And I reply
"Thanks. I've not been taking any B-12 supplement in some years now." 
Thanks again,
Theta