I reviewed the Current AVGAS Spec VS the Game commercial spec. the differences are there, They are small mostly the Game fuel has a higher boiling point and a slightly lower Specific heat of combustion the rest is pretty much the same. BOTH of these items are not very important.Theproblem w ASTM specs is they often contain"requirements" that are very very old and are not really a requirement. Now before anyone shoot the messenger. A requirement from an engineering or scientific POV is a value that can be verified by a validated method that must be met to provide minimum performance. (Standard system engineering methodology;ogy.
IN the case of specific heat of combustion…this ONLY (in the case of small changes like the 5 % in their case ). relates to specific fuel consumption . The boiling point a relic and has NO real operational import as long as the fractional vapor tests in the ball park…ie no diesel like properties for SI engines.
This would in any case be seen in the anti knock testing since that is conducted via ASTm spec in both of these documents.
summary the ASTM spec is NOT met .BUT the differences are somewhat meaningless to engine performance. AS TO SYSTEM compatibility that is NOT part of the ASTM spec anyway so no far calling on thatIF GAMI hold their commercial spec as a non changing standard.