Just saw this. Don't know how I missed it.
I started Bandit on Methyl B12 in February after she started displaying hind leg neuropathy. Even though her numbers were not as high as some numbers I have seen here. I gave her 3mg a day. It took around 6 months for her neuropathy to resolve - I am not sure if it was the Methyl B12 or her numbers improving or both. I continue to give it to her.
I started her on Neurobion last week because she had the odd GI issue and I wondered if it was on account of a B12 deficiency. I don't think that was the reason but I will keep her on it for now. I don't think there is any harm if I give it to her even if she isn't deficient.
Does Zorro have weakness in his hind legs (neuropathy)? If he does, what he needs is methylcobalamin B12 and not Neurobion which is B-complex and has cyanocobalamin B12. There are 2 kinds of B12.
These are informative articles on the subject:
https://www.felinediabetes.com/FDMB/threads/feline-diabetic-neuropathy-weak-back-legs.178252/
http://felinecrf.org/vitamin_b.htm