Correct, those values are are not stored in the hub database or accessible to apps (there was some discussion about this a while back, and it's intentional because of the amount of traffic there could be).
That is still likely your best option. You have a few ways to make this work better:
- Increase your "inactivity threshold" for that group of devices in the app you're using (my Device Activity Check) to an interval that more accurately represents your device usage
- For, ideally, small numbers of rarely-used devices that do not otherwise generate activity, consider enabling the "Refresh" option for that group -- if your devices report new "Last Activity At" data after a "Refresh," as many do
Also, consider if this kind of monitoring is even helpful for that kind of device in the first place; it's great for battery-powered sensors where you want a way to know if the battery may have gone dead, especially something like a water leak sensor that might be important and hard to see in real life or a motion sensor or remote that might at least be annoying. Mains-powered actuators are not the kind of thing likely to just "fall off" your network, and if they do, you'll likely notice during use -- and it would be good to find and fix whatever the cause for that was.
Keep in mind that, as I mentioned, you can create multiple "groups" of devices that all have different criteria. I have some with days of "inactivity" allowed due to their low reporting frequency (300-series Z-Wave sirens, for one).
