Autofocus set to a specific average HFR

In doing some exoplanet detection, it turns out that autofocus at the ideal focus isn’t necessarily ideal. Rather than having the AF choose the minimum HFR every time, the desire would be to run AF once to get the minimum HFR, then pick a HFR value as the “in focus” HFR target for the rest of the run. So, if my HFR shows a 99% quality at HFR 2.7, I’d set the target HFR to be 3.1 and then all subsequent runs of AF set the target HFR to be as close to 3.1 as possible. I realize it’s somewhat of an odd request to have the AF force a specific HFR that’s essentially known to be out of focus, but maybe others will chime in on value to them as well.
Dave

Would like to add my vote to this request - Exoplanets are also on my list, as well as variable stars. Brighter stars can be “spreadout” a bit to stop CCD pixels from saturating and provide accurate magnitude estimates. Saturated pixels are useless for these type of scientific measurements. However it must be something which can set on and off with ease on a target by target basis? I have in mind a list of mixed brightness targets - those known to be quite bright has the shift applied by refocussing - the rest are refocussed to sharpest HFR - of course a autofocus run would only be needed if there is a change from target to target - handled in the same way as filter changes?
George