One question that jumps to mind is just who is using the CPU? Is this an indication of just your usage or has the host added someone to your shared server?

mc12345678 - Can you diagram this sentence please?
While I also find that information interesting, I wonder with regards to the older version and it's highly likely security problems as compared to the newer version which reduces those known issues if there is an equivalent increase in attempts to the site thus causing more CPU time to "defend" what used to be allowed...