Stovepipe Quote - pricey

Got a quote for a hearthstone with 20 foot of stove pipe, through the wall installation, was about 12G.

Stove was like $4,000

Buy some legs 500

Ash tray 500

20' double wall 6" stove pipe with through the wall install - $5500

Labor - 2000

Now granted, I know I need a class A chimney and do not want to take shortcuts, but even when I put these numbers in - allfuel HST and duravent comes nowhere near 5Gs for 20' of pipe and through the wall thimble. I'm closer to about 2-3Gs.

Am I missing something? Seems to me numbers are off. I know the tax credit is like $2,000 MAX, so are they just maximizing on that? I have decided not to go with this quote due to the pipe costing more than the stove itself, at least until I get some competitive quotes.