Correction : after checking Bambu’s wiki we do know a bit more about the off / on / auto calibration :
Automatic: The system will determine whether the filament (and the nozzle used) for this print has been calibrated in the recent period, and whether the hotend has been replaced. If the filament and nozzle have not changed, the last calibration value will be used directly and no longer calibrated; if there is a change, a dynamic flow calibration will be performed again before printing.
On: Dynamic flow calibration will be performed before each print starts.
Off: The system will use the K value (PA profile) you set manually. If there is no profile for the filament in this slot, the system default value (default) will be used.
I actually noticed something today by using the pla basic profile on a non bambu filament and I’ve noticed some under extrusion that could be tied to the fact the flow rate calibration was set to auto. I want to run some tests. I’ll try to keep you updated.