It appears from looking at the source data that Average TOW Completion Age is exactly the same as TOW Completion Age and that Number of Cases in each row is 1. So there is no need to worry about weighted averages, just use normal averages. i.e. use AVG(TOW Completion Age)
Thanks. now that I have the calculation figured out. I want to create a dashboard that is interactive with the end users. I would like for the end users to be able change the weighted average or number of cases for Tupe of work detail and see how it effects the overall weighted average. Do you think this is possible? I added my most recent attachment to the original post.
I suggest you to mark this thread with the original question as answered and open a new thread with your new requirement.