I am guessing you are referring to this thread on STT on expired options.
The broker has an option to not exercise 3 close to money option contracts on the exchange. We would do it only if the STT is more than the intrinsic value of the option.
In case of 11000 PE, STT would have been 0.125% of 11000x75 = Rs 1000 per lot. Or around 13 points of Nifty. Since the intrinsic value of this option was 22.45 on expiry, we exercised this. So in this 22.45, after paying 13 points as STT and other charges, you still get back around Rs 10. If we hadn’t exercised this, you would not have gotten back any money at all. So in this case of yours, you would have lost Rs 750 approximately per lot.
STT, you can see on the contract note itself.
So yeah, in gist, with close to money (CTM) contracts, we will not exercise if the premium value on close(intrinsic value) is more than STT
Edit: Sorry, just saw now that you have shorted the 11000 PE and not bought it. When you short, there is no option with the broker. You get compulsorily exercised. The only time you might not get exercised is again if STT > intrinsic value (by the opposite broker). For example, if this option expired at 10990, the intrinsic value would have been 10 and STT would have been 13 points. So most likely the opposite brokerage (the client who has bought your short puts), would not have exercised, in which case you would have got to keep the entire 10 points.