“””... lower delta-T over the coil requires higher airflow for the same cooling load and we need to replace our return ducts...”””
That sounds counterintuitive. More air will absorb the cooling making the system run more. There has to be a balance. I may be presenting this wrong but it doesn’t make sense to me. Are they planning to change the blower to pull more air?
That's how it works. Higher airflow means more heat is transferred to the coolant. Cooling is not absorbed, heat is transferred from the air to the coolant.