Magento 1 extension customization needed ($15)

I have a Magento extension that allows customers to order a sample of a product please see here [login to view URL] You will see on the product page a customer can click the sample button, a product is then added to the shopping cart with no cost. The problem I am having is each product has a cost in the backend of Magento that it used to work out the profits of a product i.e Price of product is 6.00 cost to make product is 2.00 total profit in reports should be 6.00 - 2.00 = 4.00 Profit. When a customer places an order the sample products are containing a "base_cost" field in "sales_flat_quote_item" to be 2.00 so when I go to Reports > Sales > Orders the profile column is taking into account the samples base_cost, I want any samples to have a base_cost of 0.00. I have tried to modify the extension code myself by adding in, this seems to do nothing, can you help? item->setCost(0.00); item->setBaseCost(0.00); Ping me.