Q: What does "classification" mean?
A: Allow me to hand this one over to "One Of Us" songwriter Eric Bazilian:
A bit of nomenclature, by the way, for clarity's sake...
SF1 would be the two beats per chord change variant, e.g. One Of Us, Peace Of Mind, Scott McKenzie, Two Story Town
SF2 is what I'm calling the one bar per chord., e.g. Zombie, It's My Life