It really looks like he movement of steerable parachutes are FPS-dependent. If you have only few FPS, the parachute reacts slower. On high FPS (180 in my case, next to Almyra), the chute reacts really really fast. I can turn by 180° in a second. A 180° turn takes ~4 seconds on 60 FPS. I think there is a simple "time elapsed" factor missing in the calculation.
Hope this helps :)