You should try very hard to keep a consistent setting for at least a few weeks to get yourself used to CPAP treatment. If you absolutely MUST lower your pressure settings, go ahead. But make sure you are using the ramp feature when you first go to sleep and if you wake up and are having trouble getting back to sleep. Eventually, you will wake up and realize that you have no idea whether the machine is on or not, since breathing feels "natural".
It will happen. Eventually. If you keep persevering.