Great question !!!!
I would expect more evaporation at the higher speeds, but the temperature would be the same.
The A Todo Vapor (Full Steam Ahead) book uses Speed 1 for most recipes, except for one that possibly needs thickening and so is done at speed 2 and one that has a "stew" cooking for cous-cous, that is done reverse and speed soft
.
Didn't check all the recipes.
I know that I have used speeds of greater than 1 for many dishes - but probably no advantage unless cooking something else below. Rice in the basket is an example.
I use 100 degrees to steam some soft custards (Asian style)
Need to rethink my speeds.
Thanks again for a great question - love it.