Stationmaster,
You select the drives designed for the process and application.
Seen & tested in a project. I have done this. Nine drives with the same functionality, and in a tolerance load wise, with closely the same frequency supplied per phase. That is what the VSD is supposed to supply, the same frequency to either phase in tolerance. It works and can be done.
Based in RSA, we don't talk about HP anymore. We use kW. Although we are in Africa, by the way the place to be, horse power is something of the past. We are in a new area. In Africa we still use HP, but only to cart vegies in the rural areas, using horses.
Frequency limitations are subject to your utility supplier's accuracy by generating the frequency required in the tolerance.