Loss on a rolling road is calculated when coasting down in neutral. Has got nothing to do with acceleration, but everything with deceleration with ZERO power applied.

Also a different gearbox has a different loss. If the engine doesn't have much horsepower, you need a gearbox with little loss.
And the lower the road speed, the lower the loss. So a 85 bhp car can move a 4x4 car, but just not as fast as a more powerful engine.