Hi all,
My brother owns a auto repair shop in mid Michigan (Flint). I was there this past weekend (1400 miles put on the SVX over the past 4 days) and had what sounds like the same Tranny service done. My brother has used this tranny fluid flush system for about a year and says it is a great way to swap out all the tranny fluid. It works like the previous post commented but I will try to give a few more details (I am no expert).

Put about 1 pint of cleaner in tranny (thru dipstick)
Run car, shift thru each gear a couple times
Connect machine to tranny fluid line
Disconnect one hose/pipe
Connect machine in series with tranny fluid system
Run car until all fluid is swapped, some how the machine knows this. There is also a window on the machine that shows the fluid coming from the car.

The ATF machine is filled with fresh ATF. And the car actually pumps the old fluid out. While doing so there is a tank in the ATF machine that has a bladder so your car actually pumps the new ATF back into your car.

Disconnect the machine
Reconnect tranny fluid line
Check fluid level, add to full.

He gets ~$100 for the service.
He said the company that sells the machine recommends the service every 15K or 30K miles (I forget which). He said to do whatever you are confortable but he would does his every 25K miles.

We also did tires/brakes and one front CV axle, plus some other odds and ends while I was there. (Took advantage of my brother...made him work on the weekend!).

I lost my front subaru emblem somewhere on the way to Michigan...I remeber something hitting the windshield pretty hard around Lansing...if any one finds it

Drove mostly 75/80MPH and got 25 to 27 MPG.

92 SVX (silver) now has 107K miles.