NED don't sell seats and their criteria regarding Inter marks is high, for example: all seats end at 70%+ even for fields like Food Engineering etc. In regular category last year, the final Computer Science (BCIT) seats were taken at 77%.
They do have extra seats, but require around 6 lakh upfront (Self Finance seats). In my case, only 4 A Level seats were available for Electrical Engineering (compared to around 210 seats for Inter) so I also opted for Self Finance to get into EE. Last year the last Self Finance Computer Science (BCIT) seats were taken at around 66% (this percentage increases by a small percent each year).
NED's BCIT isn't THAT good as compared to FAST, NUST or IBA, but is decent.
However I'd recommend that you try Karachi University, IBA and Usman Institute. KU's new UBIT department is fantastic (I've heard this from friends who study there). IBA is improving rapidly in CS field, and Usman Institute is also a decent institute for Computer Science. Remember, for CS, you need to have skills, the university doesn't matter that much as compared to hardware engineering like Electrical E or Mechanical E.