When I had mine done, the fellow ended up busting the windshield and bending the metal trim. That required him to go read about how to install a windshield on a 300D and to buy another windshield and to replace the metal trim from a wrecker. My cost for this was $90 flat rate plus cost of ONE windshield. His cost was much higher... $150ish for the windshield isn't out of line if it's new, so $250 is fair price.

I would suggest you follow some threads on this, print them for the folks, get them to agree they'll fix it right if they break things at no additional cost to you, or overrun for labor. Many windshields today are just drop glue in place, drop windshield in place, done...