Canadian payroll records and role descriptions for the whole period, plus entry and exit records that let the officer subtract the U.S. stays. Time in the United States for the same employer does not count toward the year but does not break its continuity.
Show the subtraction rather than assert the total
The transferee needs one continuous year of full-time qualifying employment abroad within the three years before filing. Her twenty months on the Canadian payroll is the starting figure; the two U.S. stays totalling nearly five months are subtracted; the remainder is roughly fifteen months, which qualifies. The evidence that makes this credible is the payroll register showing continuous employment, a letter from the Canadian company confirming her title and duties throughout, and her travel history, which can be reconstructed from passport stamps and the official I-94 travel record. Business-visitor entries should be described honestly as software set-up and training visits; they are consistent with the organization's needs and do not undermine the case. What would undermine it is a gap in Canadian employment, a period spent working for an unrelated company, or a promotion so recent that the managerial duties cover only a few months of the year.
Hypothetical example: a produce-distribution manager spent several short U.S. visits training a related warehouse team while remaining on the Canadian payroll. Make a date table with departure, return, location, purpose and supporting record for every trip. Payroll, travel receipts, passport history and the foreign employer's letter together settle whether enough qualifying overseas service remains. Do not round up dates or call U.S. work foreign employment. The corporate documents should separately show the ownership link between the Canadian employer and U.S. petitioner, because common trade names do not prove a qualifying relationship. Assemble the time table before drafting the support letter; otherwise a broad statement of continuous service may conflict with the travel records and invite a credibility concern.