I'd expect the forces on Moonsault Scramble were higher than on the B&M flyers due to the way you enter and exit the inversions.
On Moonsault Scramble's Pretzel Knot you are swept off to the left/right depending on which direction you are going, whereas on Superman, you enter and exit on a straight line.
The twisted entrance and exit would clearly be more forceful, because your body is being pulled out of the line in which it wants to travel by the track.
For example, if you look at this picture
you can see that as you travel down the section of track on the right hand side, your body would like to continue in a straight line, instead it is whisked off to the left.
This dosen't happen on Superman, hence on Superman there is less force around the Pretzel Loop.
Of course, the speed that the inversions are taken at would also have an effect, because you would be pulled over to the side quicker. The riding position could also be significant to the amount of force.
This differance in entrance/exit could also explain the different names, Pretzel Knot for Moonsault Scramble and Pretzel Loop for Superman.