Is it better to reduce MP and leave RPM at
2200?

In my Mooney I like VFR decents at whatever speed I had been cruising. It's my
habit in cruise to keep the RPM low, almost always going a little 'oversquare'
(MP in inches a bit higher than RPM in hundreds). I don't like speeding up in
the decent, and consider the altitude energy in the bank, I spend it on haaving
the MP lower.