The way I would tackle this natively, is to have a child table of weekly hours for a task. The table would contain the first day of the week, say Sunday and then the hours for that week. I'm sure you would agree that then you could easily make your reports of task time per Staff member per week.
That way one task would have Many Weekly Hours.
The issue, of course, is how to maintain that child table automatically.
I would set a practical limit as to how many week a task can span and prevent a task form being entered more than that # of week.
Then say we allow for a max of 10 weeks.
I would create 10 fields on the task to calculate the the time for each of the 10 weeks.
Then any time a task is added or modified I would trigger an Automation.
Step 1 would be to delete the tasks children.
Steps 2 through 11 would be to create 10 children, may of which will have zero time that respective week, for example a task may only span a week or two.
Step 12 would be to delete all, the children, for that Task with no time that week.
Once you get that working, then the 1 time project would be to create the initialized values for all the children.
That can be done by making 10 saved table to table imports t import from the parent task to the children, and then mass deleting all the zero time entries..
