I am not sure if this is a simple question.
A few points of interest on this item.
Most engines are designed for cruise conditions, so bleed air is in the numbers.
747 using 2 packs instead of 3 saves fuel.
The pack inlet/outlet doors do different things according to various conditions/requests, the variations of these doors change drag and even lift due to changing airflow conditions.
Some aircraft packs can request different bleed air temp, lower I think, this can also use more fuel as a result.
Looking at the active fuel flow data of engines/apu and playing around with setting is a good way to see what goes on, an easy one is the apu with pack/packs on/off and genny on/off setting.
Also of interest, the 787 does not use bleed air off the engines/apu like older aircraft, the 787 engines don't use any fuel making air for these other systems.