There is an old message similar to this dating to 2011 with a slightly different twist. Let me explain.
In MQTT the concept of listener is important. For me the dead band setting of any device therefore depends on the requirements of the listeners.
For example, if there are no listeners the dead band might be inifinity. If there is only a chart recoder app listening the a dead band of 5 % will be adequate, etc.
To save storage and communication resources the MQTT server could manage this dead band by collating the requirements of the listeners and updating the dead band on the device accordingly.
Is there a mechanism in MQTT to achieve this?