Question on Graphs

[Thumper Buttercup]

OK guys, on our Rev-Perf unit Brian and Josh did quite a bit of tuning on the bike,
Now to me the bike pulls great, but Josh was feeling like the bike was not running
up to par.

We are running the 95cu, Larry's heads stage one, 48N cams and SE touring mufflers.

They showed me a graph that looked like this.



I had to steal someone's photo and make changes.  The line to the right was a peak
and the other square area was a flat area with no peaks.  I know this is vague but
what do you guys think would cause this flat area???

Too restrictive exhaust???