whar is the military discount exactly??how much off my bill?

Ive only got tmobile because sprint was bought out and ever since ive had tmobile i verfied my account with my military ID. I still have not seen a change in my bill if anything there are alot of inconsistancy with my bill when i add it all up with their taxes and everything and then I subtract the diacounts for my phones themselves (btw thats the trade-in discounts) my amount is completely different to tmobiles amount....(mine is less way less). I ever went one step further and had a Mathmatics Professor look and do the math and came up with thr same number as me and then asked what wualifies as the discount.? So please can someone answer what it is?. What discount does Military actually get? Because i still pay the exact dame as a non-military person would be paying...