The actual annual requirement for labor would be less if the estimated number of retrofit installations were evenly distributed over the full five-year increment of time instead of the conservative three-year increment.
Having installations every five years or every three years does affect labor costs.
mnli hypothesis: Having installations every five years or every three years does affect labor costs. premise: The actual annual requirement for labor would be less if the estimated number of retrofit installations were evenly distributed over the full five-year increment of time instead of the conservative three-year increment.