First of all, a lot of car salesmen are dumb. Not all, but then there are the ones that just plain dishonest. It's easy to confuse the two. Second, it's not that unusual for the service and sales areas to not talk to each other. I wrote software for car dealerships and the two areas were quite insular....Sales guy played dumb and claimed to not know anything about the problem even though his service department is changing one engine a week.