I know where your coming from...I also used to train as you do.
On switching my routine i did initialy find that i was associating time spent in the gym with a quality workout.
Often leaving the gym thinking "that was just to short. "This just cant be right" lol
Like you say though becoming comfortable with additional & new excercises soon takes up more time.
I now find that I push that little bit harder than before. Knowing that it will be a week before the muscle group im training will be hit next, meaning this set
has to count.
Still struggle with the time=quality mentality though