Cannot Sum Aggregate

Hi All

This is my first post to the Tableau community forums, so please excuse if this has already been answered. I'm having some problems in Tableau 10.

I'm trying to basically create a custom total column which sums the given "points" for performing a task, but I seem to be stopped by the pesky cannot further aggregate SUM as it's already an aggregate message. Here's the formula I have to calculate the points for the task.

COUNT([Ticket])*SUM([Point Allotment])

Here's a screenshot of what I'm working with, unfortunately my company DLP solution prevents me from uploading files to external sites.

What i'd like to do, for example on 3/12, is sum the 220, 55, 41.3, and 220, but when I do the subtotal function I get the following: