That seems about right. I haven't hit my first service yet but the service manager said it would be roughly 200. I am in Hawaii so it might be a little more here. I bet you cant wait to get that restrictor off.
Pay them now before they change their mind. Many of us on this board paid much more than $150. If you think about it, they will have you bike for at least an hour to an hour and a half with the removal of the limiter and a general check up, and I am certain the labor rate is at least $100 an hour.