Adhesive Anchor Critical Distance, CNa

CNa=10*da*sqrt(tau uncr/1100). Bond strength, tau uncr is 2200 per ESR and as defined in the variables and the anchor diameter is 0.625 in. Based on this equation the critical distance should be 8.88 in however the report is computing 8.839 in. I have tested different temperature ranges and anchor diameters and the critical distance equation never matches up with the bond strength variable that is listed in the report. The bond strength value in the variables is being used to compute Nba and that values matches. Am I missing a factor when computing the critical distance equation?