I used about 6-7 coats of satin poly. I lightly sanded after each coat. I did my kitchen counters with butcher block, too, and after 3 years they still look new.
To achieve the satin finish silica is added to the finish. It disrupts the flat top to keep it from being shiny. Problem is the silica weakens the finish and allows water to get into the finish where it does bad things.
It is far better to use high gloss and buff the finish to achieve the desired level of gloss. As a short cut use gloss all the way to the final coat and top with satin.
