The problem you are describing seems to suggest that you are looking to
use something like a nested multiple vlookup function (which I don't
think exists) but I could propose 2 solutions.

The first is to use a macro which sorts through your data line by line
to find the appropriate match of all 7 of your criteria and return the
rate - not complicated and shouldn't take too long to write or run; in
the form of a function it would be very flexible.

The second is to somehow combine your 7 criteria on each row into a
single unique value in a separate cell and then use vlookup using this
new value as the search criterion to find the appropriate rate.
Concatination of the criteria may suffice but depending on your data
may not give unique values.