SSRS 2005 - count rows when details row has a hidden expression (1 Viewer)

[rkrause]

Im using SSRS 2005, and i have a table thats getting me my correct data.
I have this in my one of my fields:
=IIF(Fields!ReceiptQuantity.Value < AVG(Fields!ReceiptQuantity.Value) -14,Fields!ReceiptQuantity.Value,"")
and in my details row in the visibiltiy i have this:

=IIF(Fields!ReceiptQuantity.Value < AVG(Fields!ReceiptQuantity.Value) -14,False,true)Im gettin my correct data but i havin trouble counting the the number of boxes that are being shown from the table
i tried this

=COUNT(IIF(Fields!ReceiptQuantity.Value < AVG(Fields!ReceiptQuantity.Value) -14,Fields!ReceiptQuantity.Value,""))
but get errors. any ideas?