When the skies are so bad that AutoFocus keeps failing over and over, and there is no other work to do, the Scheduler can spend all of its time focusing over and over and over. This is silly.
Instead, keep track of the number of AF failures in a row, and as this number gets larger, increase the interval between retries, up to 30 minutes. This should
not happen with Excellent sky conditions, and if it does, log it and maybe even send an email alert.
Maybe, keep watch over the Sky Condition and if it changes from anything to Excellent, reset this back-off and start trying AF again. Be careful not to over engineer this!