I can only speak for ourselves. When someone calls about any springs I qoute 1 hr per corner ($320). On some cars it takes less. We always give a worst case scenerio quote. If it takes us 3 hours instead of the 4 we quoted, then we charge 3. That being said, some people charge by "the book" like Mitchell's. Tha's what they use a regular maintenance shops. That may be the quote you got. The mitchell's guide usually quotes about double the time it really takes. WE don't have a mitchell's guide, so we quote what it takes on the hardest car...and come down from there. Some places do a flat fee. No matter how long it takes...their cost is their cost. I think that's how Mainstream does it for regular installs (no cutome work).

Hope that made sense.