Coolant Service Question (pink coolant to yellow)

[zemuron99]

Just had a cooling system service done on my 17. Requested a flush and fill with the new yellow coolant since I'm beyond the 6 year recommended interval (but only 44k miles...I know, I know). When I picked it up, I noticed the degas bottle was still more pink than yellow. I asked the Service Advisor about this, and she went to chat with the tech. He claims it was fully drained and refilled. I also noticed I was only charged for 1 gallon of coolant on the invoice. If the cooling system capacity is 15.1 qts as listed in the owners manual, it seems a full drain/flush/refill should require a little less than 2 gallons/8 qts for a 50/50 mix at the end. What has your experience been with a dealership flush/refill if you started out with pink coolant? Should I expect all the old coolant to have been flushed and the system fully refilled with the new yellow coolant? They asked me to post a review of their service, and stated anything less than 5 stars is a fail, so I have some leverage, but want to be sure I'm getting the runaround before I give them a poor review, or demand that the service be repeated with a FULL flushing of the coolant this time.