Hi Gang!
After some REPEATED experimentation, I FINALLY figured out WHY I was not hearing the desired 'fill ins' when selecting arranger style variation setups via Registration Memory buttons (1-8).

When you want to trigger BOTH the 'fill in' as well as the Main style variation itself via Registration Memory buttons (1-8), you MUST hold down Variation button (A,B,C, or D) and save the style setup into Registration Memory WHILE the selected variation (A,B,C,D) red light is FLASHING (as fill is playing).

If you want the Registration Memory Buttons (1-8) to trigger ONLY the style variation itself (without hearing the associated fill), you MUST wait till the red light STOPS flashing and is on steady (when only the style pattern is playing) before saving it to a specified Registration Memory.

Whew! I'm glad to have FINALLY figured out that out. I just hope this will help others here who might eventually encounter this on their PSR2000, because this detail doesn't seem to be covered in the manual. - Scott

PS: Don, enjoyed chatting with you on the phone today. Looks like a lot of us have gone PSR!