Question about donate

[FyX]

If i donate 8 = 10 diamonds?
if i donate 16 = 20 diamonds?
...
if i donate 40 = 50 diamonds?

 

[Roth]

8$ = 10 diamonds
16$ = 20 diamonds
24$ = 30 diamonds
32$ = 40 diamonds
40$ = 50 diamonds

 

[FyX]

so no reason to big donation

Thx for reply