This is SAP functionality where it allows maximum 5 decimals then you have to calculate it as 5 decimals do not consider excel formula where it is not restricted to 5 decimals but here it is 5 decimals.
Even though we try to modify the value of output no use since 20.60437*100 = 2060.437 round it nearest lower or upper then again it appears as 2060.437/100 = 20.60.
Even time types does not work where it is restricted to 2 decimals only better explain the same to client.
Regards
Venkatesh