Power to kWh diff column does not match wH column when viewed in statistics

Have a look at the attached image showing the statistics of 4 power monitor feeds for a graph.
Note that for each feed it shows a “Diff” column.
In this graph I’m using P2KWH feeds for this 24 hour timeframe.
Taking one feed as an example, the “emonpi:power1-P2KWH (kWh)” feed shows the following:
Min: 467.4, Max: 478.5, Diff: 11.1, wH: 22731
So where does the 22,731 wh number come from? Shouldn’t it be 11,100?
If it’s a daily number, shouldn’t it be 11,365.5?
I just don’t get it. What number is correct?
Also confusing… how can a temperature feed have a Wh column?