For RB211 engines on the 744, the function is similar; TM says :
The A/T system moves all thrust levers to the selected reference thrust. The thrust levers then remain stationary while the FMC commands the EEC to trim each engine to equalise thrust. The thrust equalisation feature is active any time the A/T switch is at ARM and the thrust levers are within one knob's width of one another, even if no A/T modes are engaged.
The thrust levers may be manually positioned without disconnecting the A/T. Except for HOLD mode, after manual positioning, the A/T system repositions thrust levers to comply with FMC thrust requirements.
Hope this helps ...
JD
