I don’t know about going back to 20 seconds... That will really increase channel changes particularly in the 2.4 band. On the 5GHz band there are, thankfully, 802.11h channel switch announcements from the AP so that a client knows what’s about to happen, where to go, and is able to resume its connection with minimal downtime. On the 2.4 band there’s no such thing. From a client’s perspective, the AP just disappeared without warning and the client is abruptly disconnected. Our default setting is 3600 seconds. In high density environments, we go 4-8 times that, and in extreme cases we set static channels. While auto channel can be helpful in dealing with changes in the environment, it can also be a case of the cure being worse than the disease.