HI,
I have the excact same problem.
The fact is that first in real life you have the real feeling of the brake lever, and second if you keep the brake pipe at 7 bar for just a couple of seconds and you return to 5 immediately the brake cylinders keep 0 bar. In game you can go to the "S" position too easiliy and even you keep that position for just a fraction of second you're pretty much screwed since as soon as you return the brake pipe at 5 bar the brake cylinders go up, so you would need to keep the "S" position to contnue driving with the brake pipe at 7 bar which is super unrealistic and also when you go to "driving" position the brakes apply hard.
Devs need either to make much harder to go into "S" position, add a brake cycilinders relase valve for each car and coach (TSW have this on some newer cars and coaches) or rework the entire brake system from the ground up