Thank you both for your insights. I think I’ll have to repeat testing in a few months and have a longer period of gluten consumption. 

The "IgA 47-310 normal range" = is the total IGA test I mentioned in an earlier test. It goes by a number of names. He is not IGA deficient.

Doctors don't usually test the levels of all the B vitamins.  B12 is frequently the only one checked.   Ask for an Erythrocyte transketolase test to check Thiamine Vitamin B 1  levels.  The eight B vitamins all work together, so they should all be supplemented.  Additional thiamine in the form Benfotiamine can be taken.  

No.  The damage done to the lining of the intestines is caused by the autoimmune response of Celiac disease.   People who have been off of gluten for an extended period may take longer to mount an autoimmune response.  Twelve days of gluten after two years off probably wasn't enough time and not sufficient gluten.  

@trents @knitty kitty would NCGS show some celiac in biopsy?