The term "flush" is really a very old term and is misused everywhere. What the machine will likely do is exchange the old transmission fluid for an equal am amount of new transmission fluid. It's not a "flush" it's an exchange.
I don't drink the BITOG Kool-Aid. A pan drop and filter change IS NOT NEEDED. The only way your filter would be in bad shape is if your transmission is failing-and then the filter would be the least of your problems. Even the post above said his filter was in OK shaped.
FYI-my position (on your asked question) is not/and will not be popular on here.
I've used a machine to exchange ATF on hundreds of units of varies makes without issue, It's when a Ham Fisted mechanic doesn't clean the cooler connections well before disconnecting them & introduces Dirt/Debris into the Cooler Return/Lube Circuit is where problems can arise.
Found a small rock lodged in a 4L80E Sun Gear lube orifice once.
Some units create more wear debris than others, Units with highly loaded Thrust Washers like the Chrysler 46/47/48RE need regular filter changes.
All transmissions create some debris during break-in, Dropping the Pan, Cleaning the magnet/s & changing the sump filter at least once in the units life is a good idea.
Then there's units that can have the Sump Filter Seal harden/shrink & either suck air or let the filter fall into the pan. 5 speed Allison 1000's are notorious for this.