22F are only used on base GT 350’s. A GT 500 car without the heavy duty battery option got a 24 f with yellow caps . The cap color indicated the lower capacity of the battery. The capacity was also in raised letters on the side of the case but that is very difficult if not impossible to see once in a car. There is no 22f topper being made that I am aware of
According to my Marti Report, my GT-350, a base model, came with a heavy duty battery. Could it be that later in production putting one size battery was just easier than specifying two different batteries?