The time displayed is the time since the device has connected, not the time of the last update.
Updates are sent every 30 seconds. If not, then the device will be regarded as offline after some time. (ok, it is not as simple as that, but that is the general idea). If the device is 'online', then there are regular updates, and everything seems ok.
In your screenshot, the device has connected at 0813, has stayed connected since then, and has probably received updates every 30seconds.
As a side note. The ASGs only send data that has actually changed. If there is nothing going on on the ASG, there is only a minimal set of data.
sounds logical, but tomorrow (to bad i didn't made a screenshot) all ASGs where in status offline / disconnected ... i will have a look on that and maybe send a new screenshot tomorrow ...