I meant a change in costs for the key to get in! Like it was the case for the Trooper dungeon after the first week. Sorry for confusion!
I'm glad now that I did not do that many runs yet, as the talisman drop rate will be increased! I did about 130 runs in both dungeons so far. It is too time consuming for me and the fact that these dungeons block your phone for other things for up to 2 hours is nasty.