I am following this thread and staying away from commenting it just to give the new members the floor since I feel like my posts are getting old
and boring.
But decided to chime in after all.
I do not believe the flushes are bad, pan and filter drop may be better but we do not really have enough sample data to make a educated decision here.
I've had my car for something like 10-11 years, bought it in 2007 when it had 30-40k miles on it.
Towing every year, plowing snow every year few on driveways, just friends and neighbors.
I had Ford do my first flush at around 60k, then at 120k, then at 182k or so.
At around 213k I was told I need a new valve body. That was the first time I dropped the pan and filter. Since that did not cure the issue and I though that I had a defective "new" valve body, they sent me another one so I opened it again maybe at 215k.
My 6R60 mechatronic replacement - saga continues, pictures..
In the end it was bad coils......but got the Mechatronic changed, twice
Then at 254k, I opened it again:
Fluid and filter replacement on 6R60
And just a month ago at 269K I did another pan and filter change.
I did it since over the summer (like every summer) I towed trailers, and on one of the trips for several hundred miles in the middle of July, my tranny temp was going over 230F so I figured, it won't hurt.
Surprisingly, the fluid looked like new and there was nothing on the magnet.
So in short:
60k flush
120k flush
182k flush
213k pan dropped, filter and fluid replaced
215k pan dropped, fluid replaced
254k pan dropped, filter and fluid replaced
269k pan dropped, filter and fluid replaced
Fluid after 15k miles including towing and plowing
I usually measure how much fluid I collect and refill same amount.