Perhaps so, but I have both T4 and Audya and I can well see someone would want to copy T4 styles to Audya, but not the other way round. And like someone said, they won't be as good as on the original KB.
Well of course they aren't. You can't really to expect conversions to sound as good as they sound on the original keyboard they were created on. That is a given ... no surprise at all. Though with considerable editing work it could be possible to make them sound as good depending on the quality of the voices on the keyboard they are being converted to. But no-one spends that sort of time doing it.