There is another setting in the phone for dimming/turning off the backlight after a certain amount of time. I've also read that on some phones (e.g. nokia) the power save setting puts the phone into "flight mode" when it cant find a signal for a certain amount of time. this prevents the phone from wasting battery while it constantly tries to find a signal. i havent had the opportunity to test this.
i think i'll try and contact LG.
thanks for everybodies help with this.