Way out of line, unless they're going to individually spray water on each seed three times daily. We should note their fertilizer prices are fair enough, I suppose, but you could DIY that for $20 per app easily, four times per year when the grass wants to be fed (May, September, October, and Winterizer).

While using good seed is always a good idea, it's not wise to mis-match your existing lawn. You won't be happy--so I'm guessing they're using a standard, off the shelf seed.

You should be able to DIY that job for less than $80, not including the water cost to keep it damp (which does mean watering twice or three times daily).