JRoatch wrote:

When I tried this

2 years ago, I found that for acceleration the time factor was always squared.

Velocity affects position over time, so it's scaled by time. Acceleration affects velocity over time, so its affect on velocity is scaled by time, but its affect on position is scaled by time squared. How to adjust depends where you're applying the scaling.

The other thing is that's an ideal model. The model of the jump might be a parabolic curve, but in practice you're probably doing an

Euler Integration, approximating it in discrete steps. The problem with this is that the approximation compounds at every step (frame), and the result can be pretty far off the ideal model, and very sensitive to small changes.

Instead of trying to do your adjustments based on the ideal model, you might just write a simple program (not on the NES) to iterate the calculation frame by frame, and just tweak the parameters by hand until you have a new arc that has the properties that you want. This lets you make all sorts of adjustments, like figuring out precisely how many pixels high the jump will be, the timing of how many frames you're above a certain level, etc. and you can also add things like releasing the jump button early to the simulation.