I've notice that in many/most scenarios the designers usually feel compelled to load up all of their CAP units with their HEAVY load out. (I've done it plenty of times.) That means that they usually have about threes times the amount of MAIN AA Missiles as they do when the planes are flying with the STANDARD amount. Looking at an F/A-18C, for example, this is the case as it has 6 AIM-120D AMRAAMs with the HEAVY loadout and only 2 with STANDARD. (Let's leave the Sidewinders out of the conversation for now since they are usually carrying the same amount regardless of the loadout.)
Now, if you elect to have the planes operate using a QUICK TURN-AROUND, then both planes will be ready in 90 minutes. (FYI....Without the Quick Turn-Around would be 3 hours.) I don't personally know anything about loading airplanes with ordinance, but it would seem to me that if you were placing 6 AMRAAMs on a plane instead of just 2, then it shouldn't take the exact same amount of time. It would seem that the time period for the aircraft getting 6 should be longer.
Again, I don't know anything about loading aircraft, so perhaps it isn't so much about attaching the weapons to pylons as it is about making sure that all of the electronics are in proper working order, so that might explain some things. If it is, however, just about the actual physical labor of attaching the weapons that takes the time, then perhaps this time should be somewhat lengthened to be more realistic? So, if 2 missiles take 90 minutes, then 4 missiles (or more) should take 120 minutes. In other words, perhaps it should be a little longer time period.
I bring this topic up because it always seems that scenarios have most of their planes loaded to the max, and then with a Quick Turn-Around they are back again, 90 minutes later, with a full load. I've tried playing many scenarios recently, ones that I am very familiar with, and I can't tell you how drastically things change if all of the CAP planes aren't always carrying the max amount of weapons, or they aren't flying again in 90 minutes with their max amount of weapons. It's much more challenging when you don't always have so many weapons at your disposal.