CSC stands for "container service charge" and are the charges by the terminal operator at the ports of origin and destination. This charges cover expenses incurred whilst the shipment is within the terminal operator's property, such as equipment used.
Container service charges only apply to ocean freight, although similar fees such as ground handling are charged on air freight.
Most likely, yes. CSC can mean various things, but if it stands for "container service charge" then CSC is the same as THC, "terminal handling charge".