I agree with the above statement and think you are getting your chain yanked!!! Time for you to take some control of your wallet, lol!!! Start with cleaning the engine real good with some simple green, cover the alt and PS cap. Once the engine is clean drive for awhile and then climb up ontop of the engine with a flash light and a mirror on a stick and start looking for the source. How do your intake boots look? If they are all oily and nasty looking , oil could be leaking from them, it will eventually drip down the back of the block making some think a rear main is bad, and it is a rare bird for a rear main to go bad on a 7.3, other common oil leaks come from the Turbo ped O rings, and the small O rings where each HPO line connect at each head. Don't pay someone $80+ per hour to troubleshoot a oil leak. This of course is my opinion, if you rely on the shop you are at their mercy, not a place a like to be. There are plenty of very knowledegable folks on this forum that will help you if you decide to educate yourself and stop the madnesss!!
NCH