Many to many relationship multiplying

Hi Guys,

I'm building a timesheet summary. In the "Projects" column, I've got a category named "ALL" which means it was time for all projects. The problem is, that manager want to split that category into existing projects.

e.g. Team member John charged:

- 10 hours on project X

- 10 hours on project Y

- 10 hours on project Z

- 10 hours on project ALL - manager wants that 10 "all" hours, to be split into X, Y, and Z on a constant ratio - 0,2 for X; 0,4 for Y; 0,4 for Z

Final outcome should be like

- 10 hours on project X + 0,2 * 10 = 12

- 10 hours on project Y + 0,4 * 10 = 14

- 10 hours on project Z + 0,4 * 10 = 14

Please note that different team members will have different ratios.

As of now, I prepared such mapping for ratios at the top, connected with data inputs at the bottom. Connected through many2many relationship.

However, i've got mind fog and formulas (sumx, calculate) doesn't work. Would you please give me advice on how to handle that correctly?