what you're describing that you believe is not valid scientifically.Tsparky wrote: There is more air coming out of the FFM port ALL the time and less out of the NP all the time with almost no air out the NP port when inhaling. I'm trying to understand the physics of CPAP so no explanation would be too technical for me... .
you've not said what machine you use, but if it's a respironics, look at the top leak line.
that's how much air is coming out of the vent ports, and leaking around the mask, in total.
compare the stated vent rates of the two masks...