We had a miele diamante plus recently installed in our new kitchen. Our city required an airgap to be installed. We have had the kitchen inspected and what we would like to do is remove the airgap, put in a high loop, and place a water filter in the hole where the airgap was. The installer had to extend the drainage hose by about 4 ft. They used 5/8" heater hose to do this and connected that to the airgap. From the airgap there is a 7/8" heater hose going to the connector on P trap. Shouldn't they have used a 7/8" hose instead of a 5/8" hose to extend the existing hose?