Here is some information.
1). Demagnetization happens one time, and then use it for calculations of all operation points.
We could run demagnetization simulation in Maxwell and then modify magnet material properties for this demagnetization. After that, we could run Maxwell machine toolkit or your own calculation for efficiency map.
2). Demagnetization happens several times for different operation points. It will be complicated in the efficiency map calculations. Maxwell machine toolkit would generate new model for the map calculations, and we might modify it with demagnetization and excitation setting. This process with demagnetization would be possible.
However, you have to carefully define the excitation for demagnetization for different operation points.