Thanks for moving it to a separate thread, John.
OK, two parts.
If a BL comp is defined in the driver, and AF uses the same number, it is actually applied twice. Always. Doesn't make too much sense (IMO). OTOH, I might have BL comp active, and set it to an approximate value. In my experience, the reaction of the focuser often isn't a step function, and for shorter moves (in the range of maybe twice the BL) the correction isn't correct to the digit. So I'd set my driver BL to 80, and the AF one to 20, to remove the last play.
If there is no BL comp from the driver, right now it uses a fixed value (not sure?) - but is that a good value for everyone?
So I think it would be reasonable to have a separate overshoot setting and not care about what the driver does at all. Have a checkbox to use the overshoot in the input field. Or, don't have a checkbox at all, and always use the value of the input field (defaulting to 100), or do nothing if the user sets this to 0.
As for what I did - maybe something stupid, I don't know. I was about to start observing (after almost 3 weeks of bad conditions), so I probably wasn't patient enough. I had switched OT to the secondary (ASI1600, DMFC with BL 139) and done an AF run. Then switched to main (ASI2600, EAF with BL 84) and did a run there. I wanted to verify that number change properly, switched back to secondary, and it displayed BL 1. Switched to primary, and that one was 0. Checked the INDI tab of the EAF, and BL comp had been disabled....
I will check again today once the devices are connected, maybe I had a bad setting somewhere (I don't focus the secondary too often, it was the first time since the switch to OTs).
But I think the first point should be considered, likely in discussion with Hy who did the first linear implementation IIRC. Already at that time I had wondered about the link to the driver BL value....