SAP IS-U Variant program to add two prices

Hi Experts,

I am looking for a variant program in SAP IS-U Billing engine so that I can add two different price keys. As per my requirement, I need to come up with the effective price after adding the two/three price keys and then multiply it with the kWh. If I am multiplying the kWh individually with each prices then the amount restricts me to two decimal places which not giving the exact value. I need to keep the kWh unrounded and the prices unrounded (may to be to 7 decimal places) and until the final value of amount is calculated. Please help me either finding a variant program or handling this scenario. Thank you. Piyush.