Trans guys might quote one price then give another on the final bill,ask if they have ever brought down a trannie of your type and rebuilt the whole trannie including a torque converter.When you find someone that rebuilds your type of trans is when I would feel more comfortable about the quote.When you do get the bill and it is higher you usually hear these words to follow,"Well ,that was just a quote"

Agreed!

Worst case scenario is that you get to know that the trans is about to go if you see metal chips.

Really a lot of that myth was created by service shops that didnt want to deal with the liability of a risky old trany failing right after it was serviced and getting the blame, and also by a lot of the fast lube places. I worked at Jiffy Lube back in high school, and we were directly instructed that when a customer asked for a trans flush and fill service, get the mileage first off, then if its over 100k, tell them you can't service it because (enter myth here). This was brought about because JL got tired of being sued for "ruining" transmissions that were worn out and people would bring in looking for a quick cheap way to get a free rebuild. Happens more than you think.

There was an issue with a local Ford shop. They had a chassis dyno that they used to let kids get speedo or power ratings till they got blamed for too many broken engines, transmissions and rear ends. Now it is for trucks only. When I got my Firebird dyno tuned, they made me sign a waiver.