Specific measurement positions are mandated to ensure uniformity. For example, for cut-edged plates, thickness is measured no less than 15 mm from the edge.
This standard specifies the requirements for the appearance, shape, and dimensions of hot-rolled steel plates , sheets, and strips. jis g 3193 pdf
However, note that tolerances differ. A plate meeting ISO 7452 may not automatically meet JIS G 3193. Always verify. for cut-edged plates