Us Hypos need optimal levels of vitamins and minerals, it's part and parcel of doing as much as possible to help ourselves. However, there are recommended levels for general health.
B12 below 500 can cause neurological problems, that is possible for people in general not just Hypos. In Japan, the bottom of their reference range is 500.
Some interesting reading
Vit D is recommended to be 100-150\nmol/L (40-60ng/ml) which you can see on the Vit D Council's website
where if you scroll down to the tables you will see
"My level is between 40-50 ng/ml
According to most standards, including the Vitamin D Council, Endocrine Society and Institute of Medicine, you are getting enough vitamin D!
My level is between 50-60 ng/ml
You’re getting the right amount of vitamin D by the standards set by the Vitamin D Council and Endocrine Society. The Institute of Medicine, however, doesn’t feel there is enough evidence to say that having a level higher than 50 ng/ml is of any benefit."
40-60ng/ml = 100-150nmol/L
Grassroots Health has a Disease Incidence Prevention Chart on their website which is very interesting
So you can see that your 37.07nmol/L falls way below the recommended level according to both the Vit D Council and Grassroots Health. Both Bluebug and I suggested the dose needed to bring your level up in your last thread.
Ferritin needs to be 70 for thyroid hormone to work, that is our own thyroid hormone or replacement. That is the level where conversion of T4 to T3 takes place. As explained in your other post, although your TSH and FT4 are in range and good, your FT3 is in range but your conversion isn't particularly good.