Viewing stats from an Agent vs Aggregate

I have a test running in distributed mode - but I've only used one Agent at this stage. When I view the statistics component and look at the graphs for Ave and Std Dev the values double when I view the stats for the Agent vs viewing the Aggregate. I don't understand this as there is only 1 Agent. I would expect it would be the same if there is only 1 Agent.?
The table logs appear to display the aggregated data. Or do they? Or will there be separate files produced per Agent? What is it that I'm viewing on my local machine?