Customized the rounding on line level by different customer

Do anyone know how to set the unit_selling_price as formula type in Pricing formulas setup?

I want to customized the rounding of unit_selling price by different customer.

So I need to get the unit_selling_price instantly and perform round(xx,1).

I can't get the unit_selling_price right now instead I get the unit_list_price.

Please advise. Thanks in advance

Step I have been done

1. Add pricing attribute unit_selling_price

2. Add procedure to get the unit_selling_price of the sales order line.

3. Set Pricing Formula Round(unit_selling_price,1)

4. Set Modifier using new price by this formula