Use accurate agreements and employment records to explain the actual stages and dates.
Avoid merging different relationships
The narrative should say what happened at each stage. A single résumé start date may be insufficient if it obscures a material change in the relationship with the company.
A strong document set lets a reviewer test the employment chronology separately from the specialized-knowledge claim. Use corporate ownership records and operating evidence for the organization link; use contracts, payroll, tax documents, leave records, and supervisor letters for the foreign employment; use training records, controlled manuals, work samples, and a detailed US assignment for the knowledge claim. Explain confidentiality limits while still providing enough substance to show what the employee knows and why ordinary industry experience is not the same thing. A first review should reconcile every date in the résumé with the payroll record. The qualifying employment period must be a continuous year in the relevant three-year period, and L-1B status generally has a five-year maximum. Hypothetical example: a marine-sensor manufacturer proposes its firmware test lead. The supporting manual names a test protocol, but the payroll dates begin after the claimed foreign year. The useful next step is not another general reference letter; it is a truthful timeline that identifies when employment began and whether a later filing date would bring a qualifying 12-month period into view.