1) can we change umisso with S4
No.
2) what is fees percent? %?
May you describe this question in details?
The way you made the price of umisso go down wasn't fair, a few days ago you make the price go down for 0.50btc/Th, and now a few days after that you make the release that will make the price go down much more with a new cloud service.
You should think a way to compensate your clients that never roi and are with you since the beginner of Umisso.