What could be the story

I was a finish painter at Mack Trucks on the cab line. There were many times I was spraying one color and when I got up to do my half of the roof I saw we were spraying 2 different colors. The worst was when we sprayed one side white and the other side red and the color was white. Try and cover red with white. We only got 7 1/2 minutes per cab for full color The line was moving through the booth at that rate.