There seem to be some discrepancies in the distances which don't seem to be actual measurements and have probably been made using some rudimentary tool like google earth. Nevertheless, I wont get into the minute details but just point out the major ones for getting the facts right.
To start with, Gulberg is located 1.5 km further inside from Islamabad Highway which needs to be added to the distance. In addition, gulberg residencia, which is the more popular scheme with investors is located an additional 6 km inside gulberg, so you need to take into account that distance as well. Also naval anchorage is located 3 km further inside from the main highway.
Secondly it should be pointed out that for some societies their may be more than one approach option. For example incase of F-17, you can use both GT-Fatehjang road as well as the motorway. The route from motorway is about 5 km longer but it takes only half the time. I had measured this myself about a month ago and the huge convenience makes paying the toll completely worth it, as it is about the same as the petrol you burn out in ugly traffic jams, not to mention the time loss.
Similarly, measurements might become different as soon as gulberg gets linked to park road and enclave gets linked to korang road.