The excellent support came back with the solution for my 50 Hz motor with speed controlled via a 0 to 20 mA signal into AI1:

"You can adjust p310 to 75Hz but the motor will be underfluxed by about 30% relative to its rating plate values if the voltage is still at rating plate.  It would usually be left at 50Hz.

Changing p1082 to 75Hz allows increased frequency as you already changed.

The set p760 to 150% OR p2000 to 75Hz.

Changing p760 adjusts the output of the AI to be 0-150% instead of 0-100% and this is relative to the 50Hz in p2000 reference frequency.

p2000 is set to the motor rated frequency but you can adjust it to 75Hz, then the 100% output of the analogue input would result in 75Hz freq."

I adjusted p2000