Working on creating a formula to use information across two cells to determine calculations in other cells

(reposted first post got removed) I'm not certain the IF formula(s) are what I need but I'm not sure what else to use. Trying to create a spreadsheet for work: the premise is that if one or two people are the Contact for a project, they will split 5% of the project's earnings, each getting 2.5%; if only one person, they get 5%. The same for if one or two people who are the Winners for the project. I need some way for the spreadsheet to be able to see that if someone's initials are under either Contact or Winner, to then give them either 5% of the net income if they are the only Contact or only Winner, or 2.5% if they share either spot with someone else. The total amount of the net income given out as a bonus will always come to 10%. The first picture shows my 'backend' sheet and a formula I was trying that would calculate 2.5% of the Net Income if someone's initials showed up on the project, but this doesn't work if their initials only show up once because then they would need to get 5%. I would also hope there would be a less clunky way to do this many calculations. The second picture is a section of the main page of the sheet showing the Contact and Winner columns, the Net Income the bonus comes out of, and then the Total C/W amount under everyone's initials that adds up their total bonuses.

Backend sheet, 'points' refers to first sheet

First sheet of spreadsheet

Please let me know if I have not been thorough enough with explaining what I'm trying to do, I'm so deep in this now that I am really really confused and just need help straightening this all out. Using newest version of Excel on a macbook, have also been working on same spreadsheet in Windows. I'm not a beginner at excel but not all that good either. TYSM in advance.