Sales Price model: contribution ratio


Anyone familiar sales price model contribution ratio is working?

Let assume i have scenario where i need ensure my sales price cannot lower then my standard cost.

Does this sales price model contribution model can help?

Assuem system setting:

1) Set the sales price model field to Contribution ratio.

2) (Assume)  Base price =Cost Price

2) Specify the desired contribution for use in calculating the sales price. Example: 100%

3) System auto propose price/discount tab > Base sales price = 200

During, SO creation, the sales price is 200.

Q1) if i reduce the price/discount tab > Base sales price = 200 to 80. how contribution ratio can help?

Q2) Can i use contribution ratio, and using the sales trade agreement to store the sales price?

Any recommend web reading which provide good example of contribution ratio working?

Appreciate the help.