rotate bytes in array

[Art]

Mike, is the compile size smaller?
I can't really check in my project because it appears code is being fragmented over several pages
after I crossed the first boundary.

Robert, Didn't know you could use a STEP -1 directive,
but if it works, it's shorter, and saves a useless byte.

It appears to be working nicely, but I will shorten it if possible.
It's for my car computer I've posted about here before.
With the vehicle running, the voltage reading is live.
With the engine stopped, but accessories relay on,
the stereo amplifiers tend to cause the voltage to jump around (understandably).
The thirty second average is then displayed and acted on to turn accessories off if the average is too low.