The extra 1, while standardized, may be some type of modifier that is manufacturer specific.
From the Koyo doc.
_ "Bearing numbers of standard bearings corresponding to JIS B 1512 "rolling bearing boundary dimensions" are prescribed in JIS B 1513__
_As well as these bearing numbers, JTEKT uses supplementary codes other than those _provided by JIS."_
Thanks again for the help, I'll post anything else I find. There is a good chart on the Enduro bearing page as well.