I guess they make time to do the necessary things to make sure things run smoothly.
We also had an air conditioner repair guy come out because we have a two story house and the upstairs and downstairs wouldn't work at the same time. Turns out the air conditioner is working fine. It is the ducts that need replacing. Or so says the fix it guy. $5200 to fix it and we will be getting a second opinion. Or just tuning one story at a time and praying for cooler weather.
We have mice and rats that get into the attic since we live so close to a big field and they may have chewed some holes in the ducts
The joys of home ownership