I think that BS.Player should save the subtitles with the "," (comma) character as decimal separator, independently from the international settings used in the users' OS.
At the moment (BS.Player v2.40.995B) BSplayer still uses international settings.
This is actually a bug, so it have to be fixed
SubRip's specifications can be changed/rewritten, but it's not the preferred solution, and the proper solution is to fix the BSplayer bug instead of changing someone else specifications