They aren't the same coil though right? ... or they are?
Just because they are the same resistance it doesn't mean they have the same amount of wraps or the same gauge/type of wire, so they could be completely different. I'm not saying they are, I have no idea, but they could be.
The PNP coils are some kind of mesh aren't they?
Either way there's no mystery, you are vaping more even if you don't notice it. It could the vapour is denser/more aerosol particles in it even if you think it's the same.