The problem deals with using a simple formula to determine the lookup value
in vlookup, if the formula (result) involves a decimal.

In EXCEL 2007, I have a table with row numbers and labels. I have another
table with row numbers that are a consistent increment higher than the first
table, e.g. 1st table row number +100 = 2nd table row number.

I want to use vlookup to retrieve the corresponding labels from table 1. For
example A4 = 11, B4 = Tomatoes. A54 = 111. To retrieve the B4 label,
Tomatoes, the formula is vlookup(a54-100,$a$1:$b$25,1,0) This works.

Vlookup will return the correct label for a lookup value of (112.5-100).
However, it will return N/A for lookup value of (112.1-100), but will return
the label if the lookup value is entered directly as 12.1.

Varying the increment results in SOMETIMES vlookup returns the label,
sometimes it returns N/A. I found that having a decimal value in either the
increment or in the initial row number makes the formula work or not work on
an apparently random basis.

Try it on a table from 12.1 to 13.5 in increments of 0.1 (12.1, 12.2, 12.3
etc.) and another table numbered 112.1 to 113.5 also in increments of 0.1.
For me, it will find a match for (112.5 -100), will not find a match for
(112.6 -100), but will for 12.6.

I think this is a flaw in EXCEL.