I think the most significant thing, here, is whether the focuser declares itself to ASCOM as "absolute " - implying that it keeps a notion of an absolute position, or whether it's "relative" - in which case all motion is relative to where you are at the start, wherever that may be... My variant on this uses non-volatile memory to store the stepper position regularly, and declares that it's absolute; it sounds like you support relative motion, at the moment, Dave, which is perfectly valid, and in some ways a more logical thing to do, since then any changes outside of the driver (manual movement, for example) don't matter. This is an excellent thread, a super example of collaboration, and thanks to all.