Is this a chronograph or a normal chronometer? I'm assuming it's mechanical to begin with.

If it's a normal chronometer servicing, that quote is probably higher than the official Omega service center. If you have a chronograph, I still think that's high (for a 3rd party job).

I'd search around your city for a reputable watch maker (and maybe even Omega authorized). Unless you have the 85xx caliber, most good watch makers can service your watch for far less.