You are not wrong. Initially, Delta did plan on using lime, orange, and purple to paint the airplanes, but as Song began to roll out, someone decided against it, although not sure if it was painting costs or what. It could have possibly been that they wanted Song to get publicity, but when your planes are flying around in different colors, Mr. John Passenger won't know the difference between the orange and the green plane and think its another airline or something. In the end, it appears that Song has decided to stick with the lime green for the outside colors. Personally, I was looking forward to the purple planes myself. Maybe as Song expands, we will see new colors brought into the light.
I don't have a microwave, but I do have a clock that occasionally cooks shit.