Why not do it yourself? I do it all the time using Amsoil ATF but Mobil-1 Atf is OK too. You'd be surprised how easy it is. No need to get under the car. Instructions I wrote earlier follow;
I don't recall, but if your car has the green plastic hose retainer, squeeze hard on the tabs to release. Metal clip is described below. Most folks buy a clip at the dealer in advance because they often break on removal.

Power flushing is a simple DIY job. I use synthetic Mobil-1 ATF or Amsoil. You will need up to 15 quarts.
Disconnect the upper tranny cooling hose. Open the metal clamp carefully (rotate it to find the split) and wiggle, wiggle, pull, pull. Cover the hose end with a baggie.
Clamp 6 ft of clear plastic 1/2 inch ID hose (hardware store item) over the hose end and prepare to drain into gallon bottles or a calibrated bucket, so that you know when you have removed about 12 quarts. Idle the engine to pump out fluid. Shut off immediately when bubbles appear in the clear hose. Add two quarts down the dipstick hole using a tranny filler funnel and hose from auto supply or chain store. Repeat the pump/fill cycle. Somewhere in the middle of this you may run the shift thru D N R while idling to assist the clean out. Once you've removed 12 quarts, the fluid should start running clean shortly thereafter, at which point reinsert the cooling hose into the radiator. Adjust the fluid level per the owner's manual. Careful not to overfill while flushing.
This is a true power flush as good as any machine! Your pump is built into the tranny.