Formulas shouldn't make a difference (although, I don't know what flatten a
formula means).

I'd review the notes for troubleshooting =vlookup() formulas from Debra
Dalgleish:

http://contextures.com/xlFunctions02.html#Trouble

wrote:

Hello. I am having trouble with a vlookup. I know that the formula
is working correctly--'s just that the data in column that I reference
first is composed of formulas. When I flatten those formulas, the
vlookup works fine, but if they are left as formulas, my vlookup just
returns "N/A." What is the trick to fixing this? Thanks!

--

Dave Peterson