It doesn't sound like it will be difficult to resolve but only if you define what it is you want it to do.
I know you can't post a data set but you could provide an example of a scenario you have currently and what it's producing which is the issue vs what it should be doing in your test cases.
Are you getting an app error for example? If yes what is it.
Once you do this I'm sure we could help you resolve your issue.
Sorry I was unclear mate
I want the three hours figures to accumulate based on what is picked on the filter
however the hours worked is broken up into three types
Full time employee
Part Time employee
Which is a filter on the front page. How do I get it so that I can do something a long the lines of updating the figure depending on what they pick?
So if the filter has Full time employee, Part Time employee, Volunteer and there are three columns for their hours worked
How do I get them to stack the sums based on what it is picked? They have the option to pick multiple choices on the filter too.
Extremely sorry; but requirement given is ambiguous.
As per my understanding, SUM(HoursWorked) expression will change it's value based on current filter selection.
Please share application with sample data. This will help us to better understand the situation and provide you expected inputs.