I am using the following array formula which seems to only work for most of
the records. I don't use array formulas much and was wondering if there are
some special consideration I need to know when using. The records that
aren't working are on random rows. My mso range is correct. The only thing
that is different about some of the records that aren't working is that the
data in $E$4:$E$1999 is sometimes a #, but the cell is formatted as general.
I appreciate any ideas you might have.

{=INDEX('ALL DLV SHPMTS'!$E$4:$E$1999,MATCH(1,COUNTIF(B84,"*"&mso&" *"),0))}