Count not counting correctly

I am attempting to creaet a colum graph to show the MoM Opens and Closes of various Reports. 
The table layout is the same between the different reports types, I have successfully used a count of the Date First Opened field to have the MoM Opens,
However when I do this for Date Last Closed, I do not obtain a correct amount. EG There are 36 closes for September in both the original Excel Table and when I look at both the Table view of Power BI,  Power Query and when I create a card filtered for the date period. However the Collum chart shows 23 closes. 

There are 13 Distinct different dates when accounting for duplicates date values.