I don't believe that "normal" blood levels were ever determined for people taking any supplements. For example, when some people use high dose B12, they can go up to 2000!

The ranges are statistical "norms" taken at random from people who do not appear ill. This may be why the lower range in US goes so low...because not everyone with low B12 has "symptoms" right away. Japan knows better, and raised theirs accordingly to 500 based on the huge event involving a drug which damaged thousands there in the early 70's. (Clioquinol aka Vioform oral).

The neuropathy from high B6 is visible, as gait disturbances, and numbness. This makes it difficult to treat, because B6 has symptoms in low deficiency areas, as well as high. I have yet to find a test result listed on the few anecdotal papers that appear on the net for elevated B6 toxicities. It is sad that further evaluation on this subject is lacking, but that is how it is still after all these years.

All you can do is stop the B6 for now if you are worried, and see if anything changes. For the most part, high B6 triggers resolve in the papers published on this topic.