..... in some cases I’ve got 6 versions of the exact same style ranging from psr3000 thru to t5. Currently deleting ...
Rikki, as you probably know, there is two fileformats, older SFF and current SFF2.
Here is some info at Jørgen's site:
http://www.jososoft.dk/yamaha/articles/style2_5.htmAlso not only filetype .sty, but .pss, .sst ... I think SX900 can read all of them just as Genos does.
PSR Tutorial site is a great resourse, but if needed, maybe Gary and others with deeper Yamaha knowledge than me would like to step in and explain it further.