Just a guess based on about 40 years of experience....

AvGas is refined to a very high standard. This adds costs.

AvGas is transported to a very high standard and some of it is lost to premium grade at the beginning and end of each batch when tanks are switched. It is called 'cut to protect' and the the tank cuts at the tank farms are always made to protect the quality of the superior product, which is anything air related.

Jet is always sent with a batch of diesel in front of it and in back of it. When it reaches the airport about 500 bbls of Jet is delivered to the diesel tank since it takes a lot of Jet to water down diesel and almost no diesel at all to turn a tank of Jet into a tank of weed killer.

The cost of the downgraded Jet or AvGas is figured into the retail price.

Delivery to Military bases is somewhat similar, but different in ways that they don't want providers to discuss. Let's just say they are 'stringent'.

At the moment there are three refineries offline in the midwest and this is impacting the price of all grades of fuel in this region. One is down for a scheduled repair job and two others went offline due to accidents. Since the trend in refinery construction for the last 40 years has been to expand and not build new then an accident at a refinery has the effect of taking three old style refineries offline.

But they should be back in a week or two, so maybe prices will inch down during the month of July.