You're going to have issues with a variable named POT since this is a PBP command, and reserved, but if you just want to alias the low byte in a word var, then use something like this;

ADPOT VAR WORD
IOUT VAR ADPOT.BYTE0 ' this is just an alias to the low byte in ADPOT.

Any value you place in IOUT will be placed in ADPOT.LOWBYTE. And whatever value is in ADPOT.LOWBYTE will also be in IOUT since it's the same RAM address as the low byte in ADPOT . It's in the manual...;o)