The drive units are the same parts assembled the same way, only base difference being component variation. Compare to ICE vehicles with cast intake and exhaust manifolds. Depending on the casting tolerance, one engine will produce more power than another. Then add on part to part dimensional stack up and one set of pistons or bearing could be lower friction than another. Some engines are built by measuring each part for best fit/ least deviation (blueprint). Based on thermal modeling ,the better drive unit can handle more power at the same system temperature point, extending the time until power limiting kicks in or allowing higher acceleration.