I was in the local hardwood store a couple of weeks ago with the missus when I overheard a conversation between another couple and a store employee. They were looking at polyurethane. The store carried what they were looking for in only satin and gloss. They were after something in a semi-gloss. I suspect that they could buy some of each and mix to obtain the desired sheen. My understanding is that it is just the amount of flattening agent that creates the level of sheen. Is that correct?