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They're all slightly different, yes.
Diverges are compact bikes, so the reach is not as long as in a pure road bike. I usually ignore the brands' sizing and look instead at stack and reach. I have no idea how Specialized comes up with the 61cm, for instance. Prob virtual seat tube, but I find it irrelevant.
What Specialized frame you're more familiar with? If you know the year I can tell you how they compare.
I'm 188cm, or 6'2"
Saddle is pictured at 80cm height from bottom bracket, if that helps.