I am not sure if those settings are configurable. If you want to make the 28 days smaller, you can always filter the alarms at the NAS until they reach the threshold you prefer. If you want to make it bigger to know about the issue sooner, you would need a configuration option.
Hub license expiration would be fairly easy to check from a script if it were really important to you to modify the behavior of the alarms (and if there is no ability to change these settings in the config file). There is a callback in the hub to get the license info, which would include the expiration date.
-Keith