Lower EPR?

Hi, I have a question/hypothesis, if my EPR/EPAP always hits a pressure of 15-16, regardless of if the EPR is set to 1, 2, or 3, is that a sign that that's just the pressure that I need and that I should lower the EPR/turn it off so the normal pressure doesn't need to go so high to get the EPAP/pressure where it needs to go? I lowered the EPR to 2 for a while, and then down to 1, and it seems as if the pressure has gone down along with it.

Also, as recommended from someone in another thread that I made, I tried a cervical collar, and all it did was wake me up in the middle of the night with a painful neck(presumably due to the inability to move as much as normal, it was one of those eliminator things), without changing the pressures required.

Lowering EPR effectively increases the overall average for EPAP pressures which can affect the prevention of the airway collapses.
So it is an option available when the machine needs more pressure (both IPAP and EPAP) to better prevent airway collapses.
BUT....those higher pressures can be a struggle to deal with for some people so having EPR available might be simply needed from a comfort standpoint.

You do need more maximum though....any special reason you are limiting the max?