I picked it up tonight. All they did so far was verify the fluid level in the differential, which of course was fine. They are apparently still on the phone with Ford concerning this, and fully expect to talk to them more on Monday. Thanks again Deysha (and Frank, regional customer service) for your assistance.
While at the dealership I spoke with the gentleman that helped me with the pinion seal replacement at 32k. I had him print out the work order, including all the materials used. Ends up that they didn't pull the cover and inspect the differential like I originally thought, so all they did was top off the oil with Ford "XY75W140QL". Since they didn't replace all of the oil, they didn't add any friction modifier, which he said was typical. Is it just me, or does this not make any sense? You make a solution of oil and FM, drain some out, add only oil - will the ratio of oil to FM be the same? I don't think so!
I am driving a lot next week for work and will be unable to get it back to the shop, so depending on how the phone calls go I decided to plan ahead and dropped the $6.62 on a bottle of XL3 which they had in stock. The oil they used and the XL3 check out according to the following lubrication specification document from Motorcraft. https://www.fcsdchemicalsandlubrican...f/axlelube.pdf
Thanks again for the help everyone. Plans for now are to see what the dealer says Monday, but I'm betting that Monday night I'll be under my car in the garage (if not tomorrow).