I am trying to understand how the INDI Focuser "main control" tab backlash setting works. When I use the simulator and enable Backlash control in the INDI tab, set a backlash value to 100 steps (for example), and then subsequently use the Ekos focus tab to manually push to a position (forward or backward), it's not apparent from the step count that any backlash adjustment has occurred. The step count looks the same whether or not a reversal has happened. Does this mean that the INDI control/device driver works "under the covers" to transparently adjust the motor position without affecting the step count as reported to Ekos? And if so, does this imply that the actual motor position (known only to Ekos as step position) is uncertain by the backlash setting?

Ok, I can answer my own question. I hooked up my focuser and did a test. The step counter in Ekos works as you'd hope it would. Backlash compensation is transparent (under-the covers) and doesn't affect the step counter. Setting BL correctly means direction reversals work as they should. You don't know the true motor/gear position to within the uncertainty of the backlash, but this is a minor detail to be ignored.
FWIW (from multiple reports), owners of EAF focusers appears to need on the order of 90 counts of backlash compensation. Having set mine, I see much improved reversal performance. I now easily sense 10-15 count moves during reversals, whereas before setting it I couldn't see any reverse motion for ~100 counts (even though the step counter increased/decreased as commanded).
Cheers, Doug

Doug,
glad you could improve your focusing experience
About the uncertainty: It is linked to remembering in which direction the last focus move went. That means as long as the EAF is powered(*) it will not lose steps and all positions should be absolute and repeatable. Shifts only occur if you, e.g., do the last move outwards, then power cycle the unit and reconnect. IIRC it will initialize with 'focus inward', and your next move command would introduce an error of 1 BL value. At least that what my conclusions were when watching it.
Since I switched to using Linear AF basically all moves always end moving 'inwards', and focus values are stable since then

(*) I think it is the EAF, but it might also be the driver. Not really sure...