For small Flight Level Change climbs and descents, the AT implements a proportionality scheme that provides thrust as appropriate to attain a programmed rate of climb/descent.
The programmed rate of climb/descent is proportional to the magnitude of the selected altitude change. For the first 1000 ft of flight level change the climb/descent rate is 1 to1 (i.e. if the change is 1000 ft the AT would aim to achieve 1000 ft/min of climb/descent rate).
For flight level change beyond 1000 ft the programmed rate becomes 1 to 2 (i.e. if the change is 3000 ft the AT would aim to achieve 2000 ft/min of climb/descent rate). Full thrust climbs and full idle descents are achieved when the target climb/descent rate increases beyond the capability of the aircraft for the active upper and lower N1 rating.
This scheme assures that passenger comfort is maintained throughout the small altitude change maneuvers where maximum climb and idle thrust is undesirable.
Don't ask me how I know ;-)