What the source establishes
ACT distinguishes physical-property checks by construction and use. Its overview gives the framework for test selection, and the button trial is a separate manufacturing check.
At the cutting table
Hold the foam, button, thread and pull depth constant. Compare the open face against the ring of fabric at the button. Check for pulled loops, asymmetric dimples and a visible backing at the deepest point.
The buying decision
ACT distinguishes physical-property checks by construction and use. Its overview gives the framework for test selection, and the button trial is a separate manufacturing check.
A tidy flat surface does not reveal what happens where the cloth is drawn sharply inward. Reducing tuft depth or changing the attachment may preserve a chosen appearance.
Send photos from the side and front plus the exact fastening description, and ask the buyer to approve the seam detail with the swatch.