C70 Windshield replacement
 

The wife's 2007 C70 has a bad crack in the windshield and today she went to get it replaced and they told her it had a rain sensor in it? The wipers DO NOT come on when it rains but I've read somewhere that the rain sensor also controls the automatic headlights. Is this correct? We do not have glass replacement (two teenagers with claims) and the premiums were a lot higher. So the first quote we got (before I knew about the rain sensor) was for $300 and now that they are telling her it has the sensor the windshield is over $700. Is this just BS or what? Took it to the Volvo dealer here in town and they told her they do not do windshields and sent her to Abra.
Any advice?
Thanks for your help.