Hello Vi, I think that this could be right but one is not directly caused by the other. Like Gerald said, if the axis from the seat to the bb moves up at the front, it crosses the pivot axis with a bigger angle. If you wanna move a hinge it's easier this way too. It's hard to move a hinge when the force direction goes parallel with the hinge axis. So a bigger seat bb difference maybe needs a flater pivot angle but not 1:1 because there are some more influences too like the weight stuff from Olaf and Jürgen. The python is a multiple parameter system where some guys have good results with a change of parameter where others destroy the stability because they changed other parameters within. Sometimes this can bring you to false conclusions. Pay attention that you look at the right parameters and the formulas might get simplified. Frohe Ostern! Steffen