This is a correct and very reasonable approach. In practice, the transformer manufacturer’s instructions and local national standards always have priority, because they reflect design limits, warranty conditions, and regulatory requirements. Any oil treatment or monitoring program should first comply with those documents. At the same time, GlobeCore’s recommendation to perform a test once per month is well aligned with common utility practice for critical units, because monthly trends allow early detection of moisture or gas growth without excessive sampling. The key is consistency: regular testing under the same conditions is often more valuable than the exact interval itself.