So if you look at the two Pressure Traces above, you can see the actual curve of the powder burning. You can see that the curve of RL-17 is "rounded", or somewhat like a plateau at the peak. Regular, or non-progessive powders are a very sharp peak and fall. The one trace of Superformance has a wider plateau at the peak. This means that the burning curve matches the expansion and flow down the bore, more closely. So you get more "push" at a given pressure peak.
In the two traces above you can see that RL-17 max loads are @ 2750 fps at 60,000. Where the Supr is only 100 fps behind, but that velocity happens down at 50,000 psi operating pressure.

A thing to remember is that Superformance being as progressive as it is, is that the burning curve changes shape with pressure. So the harder you run it, the less efficient it is. The curve begins to get "peak-y" like a regular powder. In the end, the max velocities are identical at the same pressure. But as you lower pressures, Superformance becomes VERY table top, and at lower pressures gives much more velocity returns at any given pressure. At least that is what our Pressure Testing showed over a few lots of powder. Because of the shifting curve, and the fact that powders never burn linearly, you can't reliably just do some simple math and see what pressures you are running. You can certainly do some correlation, but don't expect it to be more than that. The way to know pressures is to measure.

When we began pressure testing powders and rifles, I made an assumption about what the Starting and Max pressures from manuals were. Turns out with one powder, my assumption of what it's "happy" pressure range was, was actually pretty close. But it doesn't hold true for all of them. Also remember that if you load by weight in Grains, that grain number is not a fixed thing. There is a VERY good reason why powder bottles say "drop loads 10% when switching lots". My current 8# bottle of Superformance is about 8% different than the testing done by Hornady.