Yeah, I think that there is probably no way for there to be any difference in internal work, either, at a given cadence. If it’s dictated by the dynamics of moving the weight of your legs around at a given speed, it will be the same at least averaged over more than one revolution, regardless of whether it’s FG or SS.
I do think cyclists should take note of this data on internal work. A key takeaway is that, other things being equal, a lower cadence at the same speed is energetically favored, because you do less internal work and deliver the same power to the ground with a lower total load on your CV system.
OTOH, there are other factors, such as needing to accelerate, available strength and impact of stress on joints that will favor higher cadences in many cases.
Otto