I think so as well Jamie.  I don't believe the psychedelic state is as simple as a tryptamine binding to the 5HT2a receptor. Obviously that does happen, but to me it really feels like my brain get's set into some sort of resonance state. 

I have been able to hold onto freebase visions for up to 30 minutes with meditation(20mgs).  But I know for certain that if I had opened my eyes at anytime after the 10 minute mark the visions would likely be gone when I closed my eye's again.  This alone tells me there is something more going on.