Sum Unique Values with Conditions

Excel 2010, I have a sheet that I'm using as a base for a sheet of metrics.

Sheet1 has my data, with named ranges, and Sheet2 has my metrics on it.

I have multiple client names (Named range = Client_Name)that could be associated with a row of data, and I need to know how many unique entries occur here after filtering for another criteria (where named range Client_ClientNonClientRelated = On Site Client Related Time).

I'm not sure how to go about this. This is what I've tried, but I get a 0 as a result.

=SUM(IFS(Client_ClientNonClientRelated,"=On Site Client Related Time",FREQUENCY(MATCH(ClientName,ClientName,0),MATCH(ClientName,ClientName,0))>0,1))

Any suggestions?