On the Yamaha you can skip a fill between variations by either turning off the Auto-Fill In, OR by pressing the main variation button you are going to twice(quickly).

I couldn't see it in the manual, but maybe the E-50 will do the latter method.

Two things the E-50 has that aren't on the 3k...

1.A Half Bar button. Quote from the manual,"Certain pop songs in 4/4 contain bars that only last two beats. The usual place for such a bar is between the first and the second verse.
Another favorite position for “halved” bars is at the end of a chorus or the bridge. Pressing this button icon does not change Style playback right away. Only
when a Fill-In starts will the Half Bar function be activated and play half the number of beats of the fill
you selected."

2.A Fill Rit. button...Again from the manual, "The tempo slows down while the fill is being played. At the end of the fill, the Style returns to the previously set tempo."

I think those functions are very cool and wish the 3k(and the Tyros/S900) had them.

Ian