What does“Repeat Measurement” mean? Isn't it the same as flatness?

What does“Repeat Measurement” mean? Isn't it the same as flatness? 

A repeat measurement is a measurement of local flatness areas.

The Repeat Measurement specification states that a measurement taken anywhere on the surface of a plate will repeat within the stated tolerance. Controlling local area flatness tighter than overall flatness guarantees a gradual change in surface flatness profile thereby minimizing local errors. Most manufacturers, including imported brands, adhere to the Specification of overall flatness tolerances but many overlook the repeat measurements. Many of the low value or budget plates available in the market today will not guarantee repeat measurements. A manufacturer who does not guarantee repeat measurements is NOT producing plates that meet the requirements of Standards!

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