Not claiming how it should be, but just from my experience, the mint was enforcing 2 per President per household. I used two different credit cards with same address, each time for crossing the $750 spending requirement faster. At the second order I didn't pay attention and ordered 3 boxes, 2 of them were a President that I already ordered before. After 2 weeks the 2 boxes were canceled and the other one was delivered.
How recent were your orders/cancellations? Most of my coins have shipped within the last 6 weeks. I'm just wondering why everyone has different experiences.