I´ve little doubt that the boxes are arranged in some way.
When you need something, many weeks and months to get it. If u don´t believe me, ask those who have been looking for aGod Mode for months.
ex. if the game comes from assembling missile heats, it´s very difficult to get a swarm mark.
At one time we had even discovered a little trick. When we wanted to get a phys or heat item, the previous day we would build up energy mechs. It was more than likely that the other day appear the phys or heat items in boxes. That´s, the system interpreted was the opposite we needed.
It may be only coincidence... but I don´t believe it.