but the value returned is 9999 and 440.43 respectively.

This is what you would expect to be returned - in the second case you
have the value in your table, so 440.43 is returned. In the first case,
the value is not found, but you are not looking for an exact value -
instead, Excel returns the value corresponding to the largest item in
the table which is less than the lookup value, so you get 9999.

What suggestions are you hoping for?

Pete