Five years is the outer limit for specialized-knowledge status. A move into a managerial or executive role can be recognised by a new L-1A petition, but that is a change of classification with its own evidence, and time already spent in L-1B counts toward the seven-year executive maximum rather than starting afresh.
A promotion is a new petition, and it needs a running start
The change is not automatic and cannot be left to the last quarter. A petition asking for the executive category is judged on duties that are primarily managerial or executive, and a transferee who was promoted a fortnight before filing has little to show beyond a new title. There should be a real period during which the person has been directing others, with an organisational chart, delegation of authority and payroll records that reflect it.
Hypothetical example: a specialist from Sainte-Cécile-de-Milton is asked in year four to take charge of the American affiliate's installation crews. Filing at that point, with months of genuine supervision behind him, is a serious petition; filing in the final weeks of year five is a much weaker one. The seven-year executive ceiling also counts the years already spent, so the promotion buys less additional time than families usually assume.