Construction Span Table for Floor Deck

I was tasked to derived this construction span table from DeckCo catalog so we can show a better representation of our calculation for deck. I reference the loads from SDI and used the section properties from the catalog. I'm currently trying to derive the single span maximum length and the values I'm getting as compared to those values provided in the table always have discrepancies of 1"( sometimes higher but sometimes lower. Is there anything I missed in my calculation?