I notice this issue as well. I am running a site that, when cached, will load anywhere from .20 to .80 seconds. When it is at .20, the accumulators add up to the right amount of seconds, and equal 100%.
When at .80 seconds total, the accumulators still add up to .20, and they total only about 25%. It would appear that some loads are seeing some phantom time loss.
I am running ez on some other servers that do not seem to experience this problem. They are actually slower servers, but render pages in as little as .08 seconds.
In all cases, the servers are running a PHP Acccelerator. In the most recent case the hardware is a 8-core Xeon server with 4gb RAM, so the processing horsepower seems like it should render the page a little better.
