If you think about it, the percentage consumption is not a reading of the total battery consumed, for example:
Battery reading 90% charged (10% consumed): Screen 70%, Phone Idle 5%, Android OS 20%, Games 5%
Therefore of that 10% usage, 100% of the battery use is accounted for. It stands to reason that if you disable BT, WIFI, Accel, GPS, Sync, Notifications, that the things left to actually use your battery are limited, so the 4.3" monster display is going to register a high % usage of the battery already consumed.
Makes sense, I hope?
@desboro, try something like Easy Switch from the Market.