sim card or network = battery hog?

Hello :)
I've had this with multiple phones, that's why i put in "general" forum.
I own multiple SIM cards of different networks, i.e DPC 1800 (1800), D-Tac prepaid (1800), AIS prepaid (900) and Orange prepaid (1800).
When i put any of them (except Orange) in a phone with not fully charged battery, it always shows the same battery bars (here 6610 - 4 bars). But when i take in the Orange SIM, there will be more (6610 = 5 bars)! It also works with 8250/8310/5130 (2-3 bars) and 6510/7250 (4-5 bars). Also abouty the standby time, all the prepaids are "standby sim's", not in normal use, nobody calls them and also there are no calls made with them so if they are in the phone, it is only for testing. (use Orange and AIS for WAP purposes sometimes in the 6610).
Now, i've had all the time the D-Tac in the 5130, giving a pure standby time of about 4 days from "battery full" display to phone turning itself off because empty. Now, i've had the Orange SIM in that phone for the past 4 days, and it's still showing 3 bars even i made a 15-minutes call on the second day!
Both Networks (D-TAC and Orange) are 1800 MHz and have full coverage (4 Bars) at my location, the phone isn't moved and sits all the time on my desk. Where does this huge difference come from? Specially the displaying of a "more full" battery when using that SIM, and also the enormous longer standby time? Does Orange have a special power saving SIM? They are all 16k versions except the DPC which is the only non-prepaid and a 32k version. All of them are roughly one year old.
Please someone give me a clue... thanks in advance!
Your Thanh

Hi thanh,
Although I'm not pretty sure, but this can be happen because of three simple reasons:
1. Power saving sim cards,
2. Acuracy in reading battery charge current after sim's charge current's consumption after loading or starting, and,
3. Amount of data send by the phone automatically which is requested by the network like locale specific data.

I think you understand what am I saying, Right?

Hello my dear friend :)
I am still puzzled why three of my simcards show the exact same behaviour, just the Orange one does different......
Also before when i wwas using the 6510 (and tested that also with a 8310 and my BF's 8910) this SIM did something different. You know after punching in the PIN code, there is that message coming up "code accepted" and a checkmark, animated? Well, on the other phones (8310, 6510 and 8910) this checkmark appeared only "half" when using the Orange SIM... and ONLY with that one! It is a strange SIM...........
I should ask Orange, i guess :) And about that battery-bar phenomenon, it is not just the initial display after turning on the phone, but also still after a few minutes.... Like, it shows 6 Bars with the Orange SIM, and i change to another, it will show 5.... then i change back to Orange, and again, 6........ If it would not go back to a higher level after changing, i wouldn't be so puzzled......
Maybe i'll find out some day :)
Thank you so much.....
your Thanh

Let me know, when you do...

Best of luck...;-)