I think your reply is solid. "In theory they are not..." Sounds like a response from someone who has "read" a lot but is lacking experience in "doing" a lot regarding performance tuning. In theory, every query would be written perfectly and no tuning would ever be needed :hehe:
If you were to join this company sounds like you have a good opportunity to be a star member of the team!
______________________________________________________________________________Never argue with an idiot; Theyll drag you down to their level and beat you with experience