For me, the 767 throttles "hunting for speed" on approach drove me up a wall and I always disconnected them to stabilize the "wolf-and-rabbit" population phenomena of throttles chasing speed and vice-versa.
Although I may understand your difficulty to "stabilize the wolf-and-rabbit population phenomena" I must tell you
PJ2, that I never had to disconnect the Auto-Throttles on the A310 or B737 (except under moderate turbulence). When hand-flying, that "hunting for speed" momentum is normally reduced with good trimming technique. Unfortunately I can't say the same about all of the FBW aircraft I've flown: A320 family; A330 and A340...
When teaching on the 320, I always got my students to practise disconnecting and re-connecting the a/thr system so they had confidence in it and their ability to do so and understand.
So...they have to practice auto-thrust disconnection, hein? Did you have to "practice" auto-throttle "disconnection" on your 767, too? Or was it as easy as touching the instinctive disconnection push-button? Does this mean something about your aircraft? Or are we only "having issues" here too?
