I doubt my Russian "student" will become an olympian but then nor will I!
Well, question is, what
will your Russian student and you become?
The reason, that his cross-entry is important part of his
stroke does not mean, that your insights are not helpful for even easier or faster CSS... And you know, just changing one thing has impact to many others too and the (interesting) puzzle starts again... :-)
But if he is happy with his stroke (and you too) what shall happen? Although both of you should not forget the fun and enjoyment of playing around with some ideas, experiments and finding improvements here and there, even if they don't seem to be firsttime...