Nothing is perfect in color matching, every deck, every tint machine, every batch is different. That's why your supposed to purchase all the paint for a job at the same time from the same store and the same batch. If the color is way off then the formula is probably wrong. That's all done at corporate and they've had it wrong before. But SW employees should be able to match it manually.CHB for ceilings, dead flat.
I don't like SherScrub flat, only the eggshell.
Sherwin's computer decides what tint to put into what colors. If I am using a color from their color deck then the machine should be able to match it perfectly. It never did. I had numerous sales reps and higher ups out to address the problem. Their solution was to sell me a 5 at a gallon price when needed for touch up.
I know, I used to over buy but now I tend to under buy when I'm paying $40-$50 per gal. I dealt with SW for about 20 years their incompetence, among other things finally got to me.In a perfect world I would always buy exactly how much paint I need every time. But ...
I expect box stores to screen up. Not a paint store.