Is a profit-sharing partnership permissible with a fixed profit percentage?

In a profit-sharing partnership, they say: If you give us the capital for one year, we will give you 10% of the profit; if you leave the capital with us for two years, we will give you 20%?
Of the profit, or a known amount of dirhams?
Q: He says: of the profit, but the profit percentage changes with the increase in years?
A: There is no harm, if the profit is by percentage there is no harm, but a known amount of dirhams is not permissible.