The X-axis is the velocity, not the time. And I think one needs to be careful about comparing the amount of power available at a given speed.
So if one were to look at the power profile, with time on the X-axis, the two power profiles would compare quite differently.
For example: It stands to reason that when the P100DL reaches 35 mph, less time has passed than when the P90DL does.
So I could imagine that with time on the X-axis the power profile of the P90DL would not go so significantly above the P100DL.
So it would be interesting to see the power with time on the X-axis.