I need to return a result based on two criteria. When matching each of
the criteria, there will often not be exact matches. So, the match
should be one the criteria value that most closely is less than or
equal to value passed. Once a match is found on the first criteria,
the second one only looks the subset of records where that first
criteria matches. (Hopefully I am not being too confusing).

Example 1: Criteria 1 = .5, Criteria 2 = 7. The Result returned would
be .2.

Example 2: Criteria 1 = .1, Criteria 2 = 4. The Result returned would
be .25.

Criteria 1 Criteria 2 Result
0 0 0
0 5 0.2
0 10 0.4
0.1 0 0.25
0.1 5 0.45
0.1 10 0.65
0.2 0 0.47
0.2 5 0.67
0.2 10 0.87

What functions should I be looking at to do this in Excel?

Thank you,

Alan