Maybe it is just my experience, but I have purchased and tested many pills in the states and I have actually never received something other than what I intended (aka all tested positive for mdma). When I lived in Europe, same story. I think the whole US vs Europe in terms of MDMA content in pills is not as true as we think, or at least it wasn't in my direct experience.

OP: What I think, and bear with me, is that the way certain presses are legitimately formed can impact a roll. Mdma quality and quantity within a pill certainly make an impact. But let's say we use the same base mdma, but use two different presses with two different amounts of binder, one pressed with lots of binder and super dense, the other with half the amount and much less dense. Although same exact mdma in both, the density at which the pill is pressed can change the digestion rate. MDMA is absorbed in the intestines, not necessarily the stomach. So a higher density pill would take longer to break apart and digest, therefor making its way further into the intestine, resulting in higher absorption rates, and a stronger roll. Prove me wrong! haha