After eating the popcorn and drinking a beer, I can see both perspectives I understand where you are coming from but sounds to me that you are trying to tell the dealership how to fix the problem, because you are talking to another service center. I have build custom ski boats for 13 + years and I would not like it if someone was trying to tell me how to build it that has never built one before and the only information he was getting is from another person. Be like me tell you have to do your job!! Take it to them if it does not fix the issue then its up to the to fix again..
That's my opinion.. Hope it all works out for you..