One Anterior Tooth needs TWO Crowns !?

Hello, today I went back to the dentist after a 4 year hiatus. What puzzles me is that on my dental work plan I have one tooth - an anterior - that needs two separate crowns!? Here is what I am going to be charged, "Root canal therapy anterior $250, Prefab post $75, Crown Porcelain/ceramic substr" $575, and then LAVA Crown $325" - again, my concern is this is all for the SAME TOOTH!? I did a Google search and asked a few friends if it is normal to require two separate crowns on one tooth. I am thinking this is a billing error, is this correct? When I called my Dentists' office - they told me that that's how insurance bills - but I don't think that is correct. Any info appreciated, thanks, Jason