I don't know.
I'm going to should contact nintendo on that note.
And the funny thing is that even with shipping the japanese boxes are cheaper and still contain more.
Edit: This is what i wrote to the Pokemon TCG Company:
Hello, I am a pokemon TCG player. I play normally and i would love to say i love the game. i have noticed something that has happened over from EX to DP packs that has been bugging me. Shouldn't we get better cards in the more packs we buy? In the Moon Hunting/Night Dashing Japanese boxes, on average per box, you get 3 LV.X cards, 20-40 Rare Cards, and at least one holo per pack. Thats not bad for around 20 packs, and it only costs around $80.00 Lets look at it this way for your average pokemon box in america. On average, a person opening the box most likely will get one or no LV.X's. They might no get a holo in every pack, but they will get a rare in every pack. Heck, they might not even get a trainer card in every pack. The only good side to this is that there is 36 packs per box, alomost double compared to a Japanese Pokemon box. This is just my suggestion, but for the more money we are paying for a pokemon box, shouldn't we get better cards? When EX packs were out, I would rather buy an american box. Now i am starting to buy Japanese boxes because of the low chance of getting a Holo, a good trainer, or a LV.X. Even with only 20 packs per box, i would still be happier.