Use actual training history, work products and examples of applying the claimed knowledge. Estimates of replacement training should have an explained basis rather than an arbitrary number of months.
Distinguish learning records from predictions
Identify completed courses, supervised assignments and decisions the employee handled independently. If discussing how another employee might learn the process, state the assumptions and available supporting experience. A long training estimate is not a legal threshold. Keep the proposed US duties tied to the demonstrated knowledge rather than assembling unrelated certificates to make the file look more technical.
Internal service manuals that differ from public documentation, engineering change notices, the warranty and failure database, training materials used only for dealers under contract, and any patents or confidentiality policies covering the designs. Useful records include dated design notes showing when the route-costing model was built and by whom, change logs showing the specialist's contributions, screenshots or exports from the internal tool, and the rule tables that encode the company's pay structure. Corporate records may establish the qualifying relationship and active operations, but the worker needs an individual chronology of foreign employment, training, system access, projects, authored materials and problem-solving.