Counterweight Cost

There has been a change in plans, and I have a crane operator wanting to charge extra for adding additional counterweights. Three additional counterweights at about 22,000 pounds each are needed. I can understand the additional mobilization/transportation costs, but I don't know how much these would be for a rental rate? Can anyone help me with this? Even the full cost of counterweights this size would be helpful.

Thanks.

Counterweight Cost