One issue on the side of MV, if you have 6600V available already, but you have to buy a transformer to get 525V (or 575V?), then there will be losses in the transformer to consider for overall throughput efficiency compared to running at 6600V. The cost of those losses, compared to the added capital equipment cost of the 6600V equipment as Skogsgura pointed out, would need to be evaluated.
But from a motor standpoint, kW is kW is kW, no difference in performance.
"Will work for salami"