Managing Prices on sales orders

Hi,

I require a validation on the sales order price management.

I have set up the price agreement journals for the definition of prices per price group and my customer is associated to a price group.

When I capture a sales order, the user can change the price?

Is there a configuration to force a user to use the price from the journals or should I set the unit price field to non-editable on the sales order line?

Regards