Vlookup 8.31 problem

[dragonarss]

Can anybody tell me why this is happening?

<table width="256" border="0" cellpadding="0" cellspacing="0"><colgroup><col style="width:48pt" span="4" width="64"> </colgroup><tbody><tr style="height:12.75pt" height="17"> <td style="height:12.75pt;width:48pt" height="17" width="64" align="center">#N/A</td> <td style="width:48pt" width="64" align="right">8.31</td> <td style="width:48pt" width="64">
</td> <td style="width:48pt" width="64" align="right">6.31
</td> </tr> <tr style="height:12.75pt" height="17"> <td style="height:12.75pt" height="17">
</td> <td>
</td> <td>
</td> <td>
</td> </tr> <tr style="height:12.75pt" height="17"> <td style="height:12.75pt" height="17">
</td> <td align="right">6.31</td> <td align="right">-66</td> <td>
</td> </tr> <tr style="height:12.75pt" height="17"> <td style="height:12.75pt" height="17">
</td> <td align="right">7.31</td> <td align="right">89</td> <td>
</td> </tr> <tr style="height:12.75pt" height="17"> <td style="height:12.75pt" height="17">
</td> <td align="right">8.31</td> <td align="right">244</td> <td>
</td> </tr> <tr style="height:12.75pt" height="17"> <td style="height:12.75pt" height="17">
</td> <td align="right">9.31</td> <td align="right">399</td> <td>
</td> </tr> <tr style="height:12.75pt" height="17"> <td style="height:12.75pt" height="17">
</td> <td align="right">10.31</td> <td align="right">554</td> <td>
</td> </tr> <tr style="height:12.75pt" height="17"> <td style="height:12.75pt" height="17">
</td> <td align="right">11.31</td> <td align="right">709</td> <td>
</td> </tr> <tr style="height:12.75pt" height="17"> <td style="height:12.75pt" height="17">
</td> <td align="right">12.31</td> <td align="right">864</td> <td>
</td> </tr> </tbody></table>
The cell A2 Contains The formula =VLOOKUP(B2,B4:C10,2,FALSE)
Cell D2 contains the number for the range in B4 to start at.
Cell B2 Contains the lookup value 8.31.
B Column formula is just B4+1 etc ascending to B10.
Vlookup will find 6.31 & 7.31 but returns #N/A in A2 for anything after.
If you change D2 to 6.32 Vlookup will return all of the correct results.

Any info would be much appreciated.

 

[dragonarss]

Just for info,
I found out that if you select "precision as displayed"
Under Excel options the formula works fine using the False critera in the vlookup, I understand that when you select this option Excel uses the numbers as displayed in the cells and not the stored values that Excel normally uses in its calculations.
Something to do with floating point Arithmetic... Gotta go I got a major headache..

Thanks again for your help..