Define Rounding Rules for Currencies

Hi,

I searched on this topic on SCN but not able to get clear explanation on it. I want to understand how the Rounding Rule works in FICA and what is the logic behind the rounding functionality provided by Define Rounding Rules for Currencies node in SPRO. I am not able to understand how the system behaves when I define the configuration as attached in the screen shot. Please help me to understand the same.

Thanks

Viraj.