Hernandez concludes that staff cars should be replaced every four years instead of every three years. Why? Replacement every four years would save money, as three-year-old cars are still in good condition. Hernandez clarifies that this claim only applies to the subset of staff cars which are subject to normal use, in response to Green’s comment that some staff cars used in large areas are not still in good condition after three years.

Hernandez responds to Green by clarifying the set to which the premise that three-year-old cars are in good condition applies. By clarifying that it’s specifically the subset of three-year-old cars that have been subject to normal use which are still in good condition, Hernandez neutralizes Green’s objection.