Yes, it's best to give new fish at first a formalin bath (against Brook, Uronema and the like - velvet may or may not be targeted) and than put them through TTM (against ich). After that you observe them for 6 weeks in a QT.
With sensitive fish or fish that need a longer acclimatization it may be best to do TTM after the fish is stabilized.
Against flukes and intestinal parasites you may also consider treating with 2 rounds of PraziPro (can be combined with TTM)