Multiple currency format issue

Hello i have the following problem:

I have three currencies KRW + EURO + USD

KRW is my main currency and does not have any decimals, EURO and USD should have decimals though.

In the System Settings i set the number format to #,### - > as KRW is my main currency

i have the currency KRW setup as
Fraction Units: 0
Smallest Currency Fraction Value: 0
Number format: #,###

And euro + usd as:
Fraction Units: 100
Smallest Currency Fraction Value: 1
Number format: #,###.##

Decimals for EUR and USD will net got accepted and no decimals are displayed.

If i change the number format in the system to #,###.## the KRW will get decimals in the system again.

Does anybody has a tip for me? Thanks