Battery meter innacurate?

[jimmyco2008]

So I have a Seidio 3500mAh extended battery, and a stock HTC 1300mAh battery.

On Fusion ROM (Gingerbread Vanilla) with max brightness and the led flashlight on, Seidio loses a percent every 1:45 or so, whereas stock HTC loses a percent every 30 seconds or so.

On Uber Z (Desire Z port) with max brightness and everything turned on (Wi-Fi, Bluetooth) both batteries report about 30 seconds, with the HTC battery getting about a second less per percent.

So what's going on here, I don't know what ROM to believe, I am inclined to believe the one that shows my extended battery is BA compared to stock, but I have noticed my Seidio draining faster than ususal and it's not unheard of for them to fail within a couple of months.....

[jimmyco2008]

So I did that battery data reset in ClockworkMod Recovery, now both batteries have like the exact same battery life- 30 seconds per percent with full brightness and bluetooth and wireless tethering on.

So can someone tell me about what resetting the battery data does?
Does it mean I have to act like my Seidio battery is brand new and leave it on the charger for "2-3 hours after the charge indicator says 100%"?... I am getting about 30 seconds on both ROMs and with both batteries... that's either one hell of a coincidence or something's wrong.

EDIT: For some reason the Android OS shows significant battery drain for both batteries until around 94%, then the extended battery starts outperforming the HTC stock battery. By a lot. So now my question is, why does Android do that?

[CuhRazy]

If your extended battery is dying that fast its defective. I have the Seido battery as well and go two days with HEAVY use, full brightness GPS almost all day. Might wanna look into getting a replacement.