lvl 71 Leve - Complete Holminster Switch.
Lvl 73 Leve - Complete Dohn Mheg
lvl 75 Leve - The Qitana Ravel

And so on...

or

Leve (A) - Complete Duty Roullete: Leveling
Leve (B) - Complete Duty Roullete: Trials
Leve (C) - Complete Duty Roullete: Main Scenario

And so on...

Completing the leve gives you extra exp and some allied seals/tomes, with the extra exp comparable to a full clear of that dungeon you just did or at least half of it lol.