THC stands for "terminal handling 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.
Terminal handling 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 it is the same as "terminal handling charge". As shown below, in Panalpina's customer portal, THC and CSC are the same thing. We include the fee in the destination charges.
In Panalpina's customer portal, the THC fee is included in the destination charges.