2004 Chevy Aveo Transmission Flush requirements

Manufactures service lists a transmission flush at 60k. I took the car to a Florida Chevy dealership for this service. At my next oil change I was told that the transmission fluid needed to be flushed. I confirmed with an Ohio dealership that the fluid was dark and needed to be flushed. When I asked the Florida dealer that performed the service why it hadn't been performed they told me they emptied the pan and topped it off, which is all that needs to done. I then asked Chevy customer service and was told that the requirements vary depending on Geography and that both were correct. My car is out of warranty and I want to do the right maintenance on my vehicle. Is pan removal and top sufficient or do I need a full fluid flush and replacement?