It is all same manufacture and same quality. The only difference is for the stringer, if you are only end user, you will never feel the differences on the string. A good string reach to a good stringer(with extra care to your racket) your string less damage and long lasting. If a good string reach to a bad stringer, no matter how good is it, it will become normal string.
there're some different for sure, otherwise Japanese team (yonex sponsored) won't bring their own string (JP code) to tournament for restring, eventhough Yonex open world wide provide restring service to their sponsor players for free (string and labor).
I ve made hundreds of restringings using SP's version, many of them @ 31 lbs, no problem.
I think Yonex should try better things to do than loosing its time on inventing codes and make these messes on people's head.