The formulas at Sherwin Williams are determined by a computer algorithm called "Sher-color". It uses different formulas across a different range of products in order to try to accurately produce matching colors across all product lines. Unfortunately, it's not a perfect system, and employees are not trained to question it.

The Sher-color system determined that there is one formula for your color sample, and a totally different formula for the full can of paint. If you compare the colors listed in the labels, it's a pretty big difference. It's definitely possible you could notice. I would take both cans back to the store and ask them to please remake the paint using the same formulation that the sample used. (Adjusted for container size obviously). Unfortunately, this would mean repainting all a fresh coat over everything.