American mod doesn't make a tremendous amount of sense to me as the ideals of it don't register in my head... it's a bit like when American friends of mine start going on about "British Invasion Music". I can not get my head round what British Invasion Music is cos I'm British and we didn't invade ourselves with our own music, it was always just sort of there. I just have to keep reminding myself which British bands broke bigtime in the US in the sixties, and cling to that as British Invasion Music, and I'm learning all the time (Apparently the Searchers and the Kinks are in, but the Small Faces aren't).
American mod is very much the same as in the 1960s it seemed to be all about copying the British style. In the 60s American mod was very much about bright colours, geometric clothing... all Mary Quant, Foale and Tuffin, Twiggy and clothes that emulated their look. American mod seemed to die out when the styles Britain was producing changed from brand new far out fashions to a retro look. Granny Takes A Trip was out, Biba was out as soon as it went all Edwardian, the Bonnie and Clyde look was out, Ossie Clark's long floaty blatantly-female (not neccesarily feminine, but clothes that emphasised the fact that the wearer was a woman) clothes were out.
So the influences that created American mod died in 1968, but the stryle itself like you said was still going up until 1972 when certain people were still copying that old British style. It was still hip to look like The Beatles... but you wanted to be fun, bright, smart party-life Beatles, not strange bearded long haired Beatles who hung out in the country raising their kids and didn't care what the latest London fashions were.
Psychedelic hippie fashions were also American Mod so long as they were what I know as the "Kings Road Hippie" style. None of this spaced out, flowers in your hair, decaying vintage fabrics and slightly beat up jeans with pretty patches all over them. The Kings Road Hippie look is the posh London crowd trying to emulate that in a more stylish way (they didn't get the hippie ideals, they just thought the look was quite quirky so they adapted it to suit themselves and their own needs), so it's indian embroidery, velvet, satin and silk combined with fabulous tailoring that ensures the cut of the outfit is deeply flattering. Sort of like Edwardian smartness but with psychedelic colours. Again American mods were trying to emulate people like Mick Jagger and Marianne Faithful.
And nowadays the American mods have frozen their moment in time just like the British mods. British mods want to pretend they're with the cool, smart in-crowd of London and Brighton in 1965... whereas the American mods want to be the cool ones who know all about what sort of clothing Mick Jagger wore during the creation of a certain album, how John Lennon dressed, what Pattie Boyd wore when she was a newly wed, all that sort of thing. Both groups are copying a certain crowd in the 1960s, it's just a different crowd and a different time period... 1965 and 1966 just being the overlap between the two.
Hope that helps. It's quite difficult to expain American mod versus British mod without taking you to mod clubs in both countries and explaining what each person there is trying to re-create.