How to implement to edit both quantity and amount?

Hi Everyone.

I'm concerning about one problem. Our customer wants to edit both quantity and amount.

For example, there are three measures. One is a quantity measure, called to s_qty. Another is an amount measure, called to s_amt. Last one is a price measure, s_price.

Our customer wants to edit the s_qty measure and then wants the s_amt measure to be calculated automatically by 's_qty * s_price'.

Also, our customer wants to edit the s_amt measure and then wants the s_qty measure to be calculated automatically by 's_amt / s_price'.

The customer used CDP( is simillar to Demantra) of Adexa. The customer said that CDP provided this function ( to edit both s_qty and s_amt )