It sounds as if the pillow is just a bit too tight. Unfortunately the P10 doesn't have much adjustability in the strap. I have the same issue where the headstrap is too tight. I just pull and stretch it out as much as possible beforehand and that works well. You might have to come up with a DYI fix ...

When I look at my machine and see a certain number of events per hour what exactly is this telling me? Are those events that the machine failed to control? Or are those events that the machine detected and stopped?