True - the ASTM UL94 standard allows for various formulas for the UL 94 fuel. There is an excellence - actually an art in to make a fine AVGAS. The Hjelmco fuel which I in person designed and was recognized by Lycoming already 1995 and now with 33+ years in operations with multi millions of flight hours, thousands of various types of aircraft and under actually any weather condition is a safe fuel. Also the FAA attended the safety review Sept 15 1999 made by the Swedish Civil Aviation Authority and the conclusions were that the introduction of this fuel had less items than when the 100 LL was introduced. Also the Hjelmco fuel which is a true AVGAS is cheaper to produce than 100 LL. To summarize - request a lower price for unleaded AVGAS than 100 LL - because of this