Can't make visible/invisible values that repeat themselves in a dropdown list

[overload955]

Hi guys. I have a problem and I'm dealing with it for a couple of days already.
I have a pivot table that is made from 4 Row Labels. I'm trying to sort the data from this pivot table based on the data I have in a column called "In Analysis Date". My dropdown list looks like this:

I'm trying to check only the boxes from a certain month and year. I'm ussing the following piece of code for doing that:

For j = 1 To 400 
    dt = CDate(pvt.RowFields(2).PivotItems(j).Name) 
     
    If month(dt) = m And Year(dt) = y Then 
         
         
        If pvt.RowFields(2).PivotItems(j).Visible = False Then 
            pvt.RowFields(2).PivotItems(j).Visible = True 
        End If 
         
    End If 
Next j

This code works well except the fact that it won't check, for example, the second 10/2/2013 10:08. I don't know why this happens. Basically excel sees that item as being checked but in reality only the first one is checked. This happens for all values that are duplicated. I really don't know how to solve this. An advice from you guys will help me a lot.

Thanks in advance.