It's strange the this only happens between the amount of .71 to .79. All
other percents work just fine. Also the rounddown formula works fine.

Yes, "chart" does refers to multiple columns. The chart I am referencing is
on page 6 of a pdf file. That file can be found at the following web site,

Http://www.awc.org/technical/Perfora...wallDesign.pdf

I tried to use "=VLOOKUP(A5+1E12,CHART,B2)" did not work on all percentages.
How ever I played around with it and changed your formula to
"=VLOOKUP(A5+(1E-12),CHART,B2)". This seams to be working. I can only hope
that some day there is a fix for this "bug" cause I will forget to add this
extra formula (+(1E-12)) to a spread sheet LOOKUP function some day.

I also wont to say thanks for responding to this post. I discovered this a 3
or 4 weeks ago and have been trying very hard to find some one to give me a
fix or work around. I have been able to find a lot of Excel experts till I
point this out and I find I know more about Excel than they do, and I know
very little.

Thanks Again