Summation Meters are handy for various reasons, two of which are:
- Simplify. If you want to have more than one level of portions, for example if you want to divide the incomer energy minus all the metered shops between the unmetered shops based on square meterage, it is easier to make one summation meter that already takes all the other meters on the site into account, and then divide that meter between the shops in question.
- Performance. Sometimes a meter account will have so many meters in it (typically if you go more than 11-20 meters on a meter account, for example if you want to look at the sum of all 300 stores in a chain store); that a normal profile graph screen on that account will not perform well. You can therefore create one Summation Meter on that meter account, which will work out the sum of the meters when the meter is 'called in', and then the sum is saved in the database against one meter (the summation meter). When you then add a Meter Account on this one Summation Meter, the profile graph will then perform very well again, because the system is not summating so many meters at run time. It is only looking at one.
To come back to your question:
Basically, when a summation meter 'calls in', it cannot go beyond the maxdate of the oldest component meter. Although, if a meter is uninstalled, it will go beyond that meter's maxdate, because that meter can never call in further again in the future.
I've looked through your list of component meters, and it seems there is one that is disabled, BUT NOT UNINSTALLED.
So, basically, what that means is that it is temporarily not shown on your problem meter list, but as soon as it is enabled again, it will read in again.
To make your summation meter carry on reading in beyond this point, uninstall that disabled meter to make it permanently disabled.