Ration on report painter

Dear community,

On report painter I have created a P&L with 15 column (for each company)+ 1 column sum "COMBINE". On each column I have a ratio through a formula % du CA EXPLOITATION = EBITDA / TURNOVER.

1 - How can I set this specific cell in %

2 - In the column Total "COMBINE" the ratio is not working, it's a sum of all the ratio which is wrong, How can I force the formula (instead of the sum) here?

Thanks a lots for your help