2 nights Kumamoto and 3 Aso or 1 Kumamoto and 4 in Aso?

so far our itinerary for 2 weeks in Kyushu in March is

4 nights in Nagasaki, 1 night in Unzen, 2 nights in Karatsu, 2 nights in Kumamoto, 3 nights in Aso and 3 in Kagoshima, which will be followed by a full week in Tokyo. but I'm considering swapping a night in Kumamoto for another night in Aso to give us more time to explore the beautiful countryside of central Kyushu. we'll be renting a car after Nagasaki so will have plenty of freedom to drive around.

Any thoughts are welcome.