Many many years ago when I was an apprentice at B-Cal, Cal Air (were using their DC10-10's for short haul trips rather than the long haul B-Cal used the 10-30's for.
It was my turn in the tech department and was given the task with a couple of others to go through all the maintenance logs etc to try to prove that this was costing us more money to maintain. We actually proved the opposite so it was swept under the proverbial carpet.