IMO and experience, satin poly levels out just fine and is actually much more forgiving than gloss. However I'm talking about spraying it with a gun, not wiping on. I've been using satin poly exclusively on my necks for about 4 years now. And I have even stripped and re-sprayed some of my gloss poly and lacquer necks because I like it so much better.

I personally don't see any benefit to laying down gloss just to go over it with satin later. Satin builds the same as gloss IME and I generally don't need to do any sanding with satin unless there is a significant blemish (or a bloody insect lands in it while still wet! - happened more than once!). If I need to sand, I will follow it with a fresh coat and hope I don't have another blemish. (it's easy to spot spray, so not necessarily a full re-coat)

Polishing satin or "satin-ising" gloss do not really achieve the same result as their individual intended appearances.
In very basic terms, satin poly gives its appearance because it has a higher amount of solids in which light is refracted, where a with a gloss, it is reflected.

Because of this, a polished satin will be "shinier" but still not really look the same as a true gloss, and a de-glossed gloss (huh???) will have a satin appearance (and feel) but will still not look the same as a true satin.