software

I have the following two tables, the first lists the Employee Increase Dates
and the Amounts, the second table has the Employee and their Pay Date. In the
second table I need to lookup the Amount equal, or prior, to the Pay Date.
For example ID737924 and Pay Date 31-Aug-02 should show Amount 14,850. Bob
Phillips has been helping me with. His suggested formula was
=INDEX(C4:C28,MATCH(MAX(IF((A4:A28=A30)*(B4:B28lt;=B 30),B4:B28)),B4:B28,0))
where C=Amount, A=ID and B=Increase. However this formula will work on a
small sample but when applied to the live data it usually returns an error
(#N/A). The data is in excess of 20,000 entries. In addition the ID can be
numeric or alpha numeric and I have spilt the ID into Numeric and Alpha
Numeric sections. Bob has been a tremendous help but I wonder if anyone else
can suggest another solution?

IDIncreaseAmount
73792406-Feb-0115,500.00
73792401-Sep-0114,850.00
73792415-Apr-0214,850.00
73792401-Sep-0215,225.00
73830205-Feb-0127,500.00
73830201-Sep-0128,875.00
73830201-Sep-0229,750.00
73857501-May-0116,500.00
73858301-Sep-0029,000.00
73858301-Sep-0127,400.00
73859101-Sep-0044,000.00
73859101-Sep-0148,000.00
73859101-Sep-0251,000.00
73860901-Sep-0024,229.92
73860901-Sep-0123,653.34
73860915-May-0223,653.34
73860901-Sep-0224,200.00
77310112-Mar-0140,000.00
77310101-Sep-0138,600.00
77310101-Sep-0239,370.00
79943705-Mar-0111,000.00
79943701-Jun-0114,000.00
79943701-Oct-0114,500.00
79943701-Sep-0214,900.00
79943702-Sep-0215,000.00
IDPay Date
73792430-Aug-02
73792430-Aug-02
73792427-Sep-02
73792427-Sep-02
73792425-Oct-02
73792425-Oct-02
73792429-Nov-02
73792429-Nov-02
73792420-Dec-02
73792420-Dec-02
73830225-Oct-02
73830225-Oct-02
73830229-Nov-02
73830229-Nov-02
73830220-Dec-02
73830220-Dec-02
77310130-Aug-02
77310130-Aug-02
77310127-Sep-02
77310127-Sep-02
77310125-Oct-02
77310125-Oct-02
77310129-Nov-02
77310129-Nov-02
77310120-Dec-02
77310120-Dec-02
79943726-Apr-02
79943726-Apr-02
79943731-May-02
79943731-May-02
79943728-Jun-02
79943728-Jun-02
79943726-Jul-02
79943726-Jul-02
79943730-Aug-02
79943730-Aug-02