No matter what the Proofgrade numbers are you can run a test with this design and see real results with real numbers.
But first, of course, make sure everything else is up to snuff. That the head fan is blowing the smoke forward and all the lenses & windows are clean. The tiniest speck on a window can seriously reduce the power where it needs to be and if you see the smoke catch fire even for a short bit, that will also seriously degrade the power while that is happening. A couple weeks use can certainly be enough to call for a maintainence cleaning.