SG76
Your logic is sound, but... Slightly missing the point; if you have intermittent fuel feed, there is no difference between what you're going to be able to achieve whether in Auto, Mixed mode or Manual mode.
Dependant on the exact cause of intermittent fuel you may get benefit in crossfeed, or more likely, in Prime.
I do think (sometimes due to uncertainty about the system), it's a big ask to expect pilots under duress to operate an emergency procedure that has no effect for the 1st 2-3 inches of movement (dependant on potentiometer thus stepper position). Much easier to just "Freeze the sucker", continue in proper Manual.
Doc