The HurriSheet at the top of the page is an expanded version of the Saffir-Simpson Scale and includes storm surge and wave height estimations and approximations.

The left half of the sheet is mainly for estimating maximum wind speeds from the storm's barometric pressure as reported by NHC and reconnaisance aircraft. I used 1000mb for calculations on this side of the page.

The right half of the sheet gives Storm Surge, Significant Wave height and wave period estimations based on barometric pressure.

I used 1013mb for calculations on the right side of the page.
1013mb may be used for all of the calculations. The result will be lower maximum wind speeds and higher surges.
Not entirely a bad idea since Surge Flooding results in more deaths than wind.