Why not just hack the cgi and unlock your fan setting?
Or, one
could just accept that the manufacture might know a
little more about what the
right speeds are...

In principle, agreed...but unfortunately that has not been the historical record...

Hey here is how I look at it.
F2pool can mine with older s9s if they lose out doing this it is on bitmaintech and since f2pool is run by bitmaintech they get what they deserve.
Over the next month I will buy another Avalon and point it here.