If a substitute standard has been used in a limited calibration, which explanation is NOT expected?

When a substitute standard is used in a limited calibration, it is expected that certain conditions apply. The understanding is that a substitute standard is typically employed on a temporary basis, often because the original standard is unavailable or unsuitable for the specific calibration situation. Therefore, it is rational to expect that the substitute standard was used only for a limited time until the primary standard can be reinstated.

The assertion that a substitute was more accurate than the original is not generally expected when using a substitute standard. In fact, it is often the case that substitutes may not meet the accuracy or performance capabilities of the original standard. Calibration procedures are designed around traceability and accuracy; thus, introducing a substitute that is purported to be more accurate disrupts that validation and could compromise the integrity of the calibration process.

The other options reflect common practices and expectations in calibration scenarios. Each indicates a relationship to the temporary or limited application of a substitute standard, which aligns with how calibration processes are typically documented and justified.