bugsiegel,
I agree with your assessment and with the actions you took to repair the transmission leak.
I do not believe that transmission need a detergent flush, which seems to be what Ford dealers are pushing....It's just a gimmick to jack up the price of a transmission flush.
I am a big proponent of transmission flushes over conventional drop-the-pan fluid changes for a number of reasons that I have spoken about numerous times here.
I also agree with your paranoia regarding shops that may flush your tranny with the wrong fluid. I avoided this by asking in advance exactly what fluid would be used on my Sport Trac and then verified that it met the proper Mercon fluid specs. The Kwik Lube center I used for my Sport Tracs used a Pennzoil brand of Mercon-V fluid. I would never use some unknown brand because the Shop get's it at a discounted price.
An alternative method would be to ask the shop if you can bring the fluid of your choice to use and only pay for the labor for the flush. Of course many shops might balk at that, but you can always ask and some will be glad to accommodate your request....and if not, you can always walk away.
...Rich