How can I understand the output?

[shaunhurryup]

First of all, thanks for the plugin , it provides the exact numbers that I can report to my boss when I write the technical proposal.

As a beginner, however, my first feeling is that the general output time should be plugin plus loader, which like

 General output time    =          Plugins      +       Loaders
  28 min, 51.47 secs     =    About 27 mins     +    About 85 mins

I cannot figure out why the time doesn't match, and how should I understand it?

Thanks for your kind answer~~~