Price in SO

Hello Experts,

I have configured 4 prices in my pricing proc.My client has 4 prices based on daily weekly biweekly and monthly.But when i try to create Sales order system is picking the monthly price initially in NETWR.Rest all will be inactive.If the user want to charge for biweekly,user will have to take out the montly price

Aft taking out the montly price manually,system is picking the biweekly in the NETWR.User does not want to take out manually.Withouht taking out manually how will the system will update in the NETWR.Or is ther anyother alternative wher i can maintain 4 price