Mysterious bug on excel calculation, on a vlookup

Glarrain  wrote: ``A7 and A8 looks like a 100% like the one on A11 and A12``

And looks can be deceiving.

The problem has nothing to do with errant characters (which would result in #VALUE errors, anyway), and using the Excel VALUE or VLOOKUP(...,TRUE) function might work-around the problem only by coincidence.

Instead, this is just yet-another example of binary (floating-point) arithmetic anomalies.

The work-around is:  whenever you expect a calculation to be accurate to some number of decimal places, explicitly round to that number of decimal places -- and not to arbitrary number, as some people suggest.  For whole percentage values, round to 2 decimal places (because 12% is 0.12).  For percentage values that should be accurate to 2 percentage decimal places, round to 4 decimal places (because 12.34% is 0.1234).

It appears that the values in A7 and A8 had been calculated (somewhere), then copy-and-pasted-value into A7 and A8.  And the calculated values are infinitesimally smaller (-1.11E-16) than how the values appear, even when formatted to display 15 significant digits.  We can see such differences with formulas of the form =SUM(A7,-(A7&"")) formatted as Scientific or General.

(That works because the expression A7&"" returns the value formatted with up to 15 significant digits.   That is Excel's arbitrary formatting limit.  It is not the limit of numeric precision, as many documents state incorrectly.)

Additionally, VLOOKUP is among the many Excel functions that compare exact binary values, not the values arbitrarily rounded to up to 15 significant digits, as compare operators ("=", ">=", etc) and the *IF[S] functions do (COUNTIF, SUMIFS, etc).

Since the value in A7 is infinitesimally less than the value in A4 (exactly 100%), VLOOKUP(...,TRUE) returns the value in column B (B3) that corresponds to the largest value less than 100%, namely 95% in A3.

Since the (same) value in A8 is infinitesimally different from the value in A4, VLOOKUP(...,FALSE) returns #N/A because it fails to find an exactly binary match.

In both cases, one work-around is to use ROUND(A7,4) and ROUND(A8,4) if you want to allow for accuracy to fractional percentages (2 percentage decimal places), as you format them.

Another solution is to explicitly round the calculations that sourced the values in A7 and A8.  You do not show us those formulas.

Neither solution is more "right" or "wrong".  The choice is yours to make, depending on your intentions.