Ok, got my 2 booster boxes. One thing I did notice was that the packs weighed either 19.7-8 that had holos/EXs and that the FA pack actually weighed closer to non-holo at 19.5-6. However, there were holos in that weight range, but only a couple, and most of them fall in the former weight range. The final weight range I found was 19.3-4 which contained only non-holo rares. From this I can pretty much say with reasonable certainty that you cannot weigh 36 packs, and pick out just the EXs/FA and sell the rest off. Not to say that someone cant buy multiple boxes and just open weighed packs and make a box to sell out of leftovers- but it would require alot of time and effort. FYI though- Anime Forever, Troll and Toad and Gathering Grounds were the places I ordered my packs/boxes from and I pulled 3 EX per box and 2 from the 24 blisters I ordered from T&T. They are for sure reputable and legitimate so have no fear if ordering from them. The boxes were not tampered with either in any way shape or form. Local card shops would probably be the only place I would be wary of buying loose boosters or blisters- IF they sell singles too, which most do.
On a side note-
Out of 4 boxes and 24 packs I pulled 3 Mewtwo EX, 2 Zek EX, 2 Regi EX, 1 Kyurem EX, 2 Kyurem EX FA, 1 Zek FA, 1 Shaymin FA, 1 Regi FA, and 1 Mewtwo FA ( I was quite lucky with the Mewtwos- but selling them off wouldnt cover the 400+ I spent so its still a bit of a loss).