Careful with the details. 35m is the release clause Galata are almost guaranteed to pocket in 4 months of time. Easy money.
Galatasaray will pay Roma €16.5m plus €13m in add-ons, half of which are easy to achieve and some of that are more difficult.
Read my post above

Galatasaray are being used as a proxy club so Inter get the least money out of the 15% transaction fee, while Roma have inserted a future resale clause set at the same 15%, which would earn them another €5.25m when the release clause will be triggered.
Basically this kind of a deal structure is a WIN-WIN-WIN for Zaniolo-Galatasaray-futureclub (Milan?).
Sky: Roma have right of first refusal on talents Yusuf Demir and Efe Akman.
Inter come out the losers out of this.