Hi Anthony, I just tried to solve your problem.Yes, u are right the fill ins remain
there even after deleting.

SOLUTION: 1) while u easy rec do not add fills
on the fly. 2) After recording all your song
(without fills)now its time to add your fills
using to record control track.Now u are free
to add or delete fills using step rec(control)track.I did all this on my kn6500
and i do not know yours.