Relationship between columns at PO Distribution Level

Hello Friends,

Can somebody plz help me in knowing the r/p between Ordered Quantity, Amount Billed, Quantity Canceled, Encumbered Amount and Active Encumbrance Amount at PO distribution level.

I know what these terms mean individually but want to know the exact r/p if one is known how to calculate other.

Your help will be much appreciated.

Thanks,

Rohit.