I have an excel macro worksheet where I use a vlookup function. I originally set up the formula as this:

=IF(ISNA(VLOOKUP(K1 & "_" & TEXT(A23,"yyyymmdd"),WeeklyHistory!A$1:$ZZ$9000,8,"false")),0,VLOOKUP(K1 & "_" & TEXT(A23,"yyyymmdd"),WeeklyHRHistory!A$1:$ZZ$9000,8,"false"))

but when I run the macro it changes it:

=IF(ISNA(VLOOKUP(K1 & "_" & TEXT(A23,"yyyymmdd"),WeeklyHistory!A$1:$ZZ$8955,8,"false")),0,VLOOKUP(K1 & "_" & TEXT(A23,"yyyymmdd"),WeeklyHRHistory!A$1:$ZZ$8955,8,"false")).

If I run it a third time it reduces to $ZZ$8820.

The number of lines it is going down is the exact # of lines I clear out and reload each time in the WeeklyHistory tab. So I know what it's doing, but WHY??? How do I keep it from changing each time?

Thanks.