The main problem is with your data source options for you chart. The chart you describe is typically created on a layout based on the table storing the data to be charted, tasks in your case. The y series (wedge size) would specify a "count of" summary field and you would sort your records by task status to group your records by status and thus get one wedge for each status instead of one wedge for each task. You data source options need to be the ones for "found set" and "summarized data".
In fact the dashboard is based on the project table, in order to list the active projects, and show the project revenue chart. In this scenario it seems when I choose the suggested "found set" and "summarized data" options, I lose the sorting associated with "related records" (I lose the option). Do I have to create a summary field for each task status at project level to get this to work, surely not?
Mistakenly said I was on FM Pro 12, but it's 13, sorry for that.
That's one of the key points that I was trying to draw your attention to. In my last post, I stated: "The chart you describe is typically created on a layout based on the table storing the data to be charted, tasks in your case."
If your layout is based on projects, the above method doesn't work and there is no simple way to get the wedges to represent summarized data.
It can be done, but it's not simple.
One option is to use a script to generate the chart on the tasks layout and then copy the chart image into a container field in Projects. You can use GetLayoutObjectAttribute to access a chart's image.
Another is to use the delimited data option and use Execute SQL to create some return delimitted subtotals--one for each task status.
A third is to set up a related table where you have one record for each task status. These records then link to your task records by ProjectID and TaskStatus. A calculation field using count can count the records in tasks with the matching project ID and status and you now have one related record for each wedge of your pie chart where your wedge size will refer to this count calculation in the related table.
As you say, it's not simple. This is clearly not something FM is currently set up to do, so I will seek a different approach.