Daniella,

It seems to me that when we discussed this before we discovered that it was the time that did or did not elapse between supplementation and tests. A few days without B12 before the test can make a great difference, because if there is not a few days without any B12 before the test, extra B12 that is not sticking with you will be measured as well.

Of course there are other possible factors too: for instance, certain things in the diet can be measured as B12 when actually they provide no usable B12. But that is less likely to be the case, because you would have had to change your diet drastically and abruptly.

If you do not malabsorb severely you absorb plenty from a B complex or even many multivitamins to get your level up very high (which is fine). That does not mean that you were not deficient or that you won't be again eventually if you stop B12 for a VERY long time.
Apparently you store well, which is a good thing.

The only problem is too little B12, not too much.

rose