When I select a level difficulty for Atlantis (for instance hard), the system remembers the next time the selection. This is ok, but the selection is applied to season III, also. So I switch to season III and the default level is now hard.
Example: I was working season III levels on hard difficulty. I wanted to do some Dense Fog Atlantis levels for POV. Enter 9.8 and spent 3 tickets, without noticing that the switch was also on HARD. I had previously left the switch for Atlantis on normal.
So any change of the difficulty switch on Season II or III changes the difficulty for the other Season, too.