Its not explicit, and I wonder if that is not a strategy to sell as many tickets as possible at $390. Because no one is going to miss out because of a $150 difference, not with all the money invested in all the other necessary things to be at this event. I mean, if there are more $390'ers than there are $240'rs, why not sell the $240 tickets to the $390'rs either at the time or in the post-main sail which is ALL $390's?
Given all that Burning Man entails, most people will opt for the $390 if it means getting in, without realizing that the lottery only happens WITHIN tiers.
This tier business is something else, and even if inadvertent, a very clever marketing scheme.