Heaven forbid we spend too much time with patients! (ha ha!)
My family doc (who happens to be a DO) explained that he knows when certain patients want/need the extra time. Others just want to come in, get treated, and get out. He's got the flexibility, and the experience, to listen to them and treat them the way they want to be treated. His schedule balances out.
And, by the way, he utilizes OMT in his practice. The way he maximizes his efficiency is to have the nurse bring the patient into the OMT room, have them lie on a heated massage (rollers) table for ~10-15 minutes---he's treating other patients while the person is being "prepped". Then, he's able to come in and perform the OMT on a prepped patient; I've had it done, and he spent about 30-45 minutes with me...
Point is: I'm sure we can all find ways to spend the time we need with our Pt's. You just do the best you can with what you have...