Can I lower or turn off my over-usage approval?

Yes, at any time, from the Plans page under "Over-usage billing": enter a lower maximum, or 0 to turn paid additional usage off, and save. The change applies immediately. Additional tickets or sessions already used remain payable, but no further paid usage is allowed above the new maximum. If the price per ticket or session ever increases, your existing approval does not cover the higher rate and Deskhero asks you to approve again.