Problem with If and sumproduct formulas

Hi,

I have a sheet that contains rows containing letter codes for example "CU". This is generated by an IF formula i.e. If true = "CU". However I need to be able to calculate the number of instances of "CU" but sumproduct will not work as it sees the cell as containing a formula not the result i.e. "CU".

Sumproduct code:

=SUMPRODUCT(D58:D61="CU")

If code:

=IF($A58="","",IF(D$5="RD","RD","CU"))

Thanks in advance