N0UU
Not sure how Ham Radio Deluxe does it, but you just enter the offset for
whatever frequency you dial to (after setting up the offset bands) and then
whenever you "tune to that frequency, it applies that offset. So you can
use one of the various signal sources to find the error for that band, a
quick calculation and you plug that offset in. That automatically takes
care of whatever error the system has (until you drift!)
Easier than my remarks. Should be easy to implement.