Interesting information! We just got scammed in White Stone, Virginia... we chose the same color, but went from a flat to an eggshell finish. I wasn't available to stand over the painter while he painted. For such a detailed job, I marveled at how quickly he finished the project! After he was paid for the job, we discovered all he did was roll paint across the walls and close to the crown, baseboards and detailed trim around windows and doors leaving about an inch or so of the flat finish. By using the same color, he didn't even do the job he was paid to do, which explained why he could finish the job so quickly. By using the same color... he got lucky and passed it off as a completed job not bothering to paint to and cut in around the trim. Upon further evaluation of our walls we could see exactly where he stopped because we could see the difference between the flat and eggshell finishes. There are walls he didn't even bother to paint. Then where he did paint near the crown when we were in the room watching ... he hit the crown moulding and tried to tell us it was already there... and tried to sell us on painting the crown moulding. I am so disgusted and upset!! He'll be hearing from us to rectify the situation.
I used to work at Sherwin Williams. The best thing to do is specify that you will purchase your own paint. If the painter objects strenuously, he was plaanning on making money in the ways this article outlines. You might pay a few dollars more for paint, but you will have control of the quality of what goes on your walls. Never skimp on paint quality.