Error using dates with HLOOKUP
 

I have a workboot where sheet 3 gets data from sheet 1. Both have the same
unique identifiers in column A, and both also have the same dates in row 6.

A B C G L
4-Jul 11-Jul 18-Jul
6 Al A $7.01 $15
7 John A $8.32 $6.90
8

I have a formula that calculates the proper column to get data from, but it
depends on it's own column for the calculation. i.e. (COLUMN(D1)-3)*8-1
What I'd like to do is use hlookup to find the column in the other worksheet
with the same date. I'd prefer not to use a index(match()) function, as I'm
already using it.