There is a slight difference in between the CCTR and PCTR.
PCTR is created in SRM and valid as local source of supply. In other words it is valid only for local and Extended classic scenario.
However, CCTR works first as local SRM contract and can be distributed on item and purchasing organization basis to one or multiple SAP ERP backend systems. The leading contract for price determination is is the SRM contract. The distributed contract in ERP is also read only (changes only via SRM central contract) but regarding source of supply determination it behaves like a contract created directly in MM.
I hope this will help. For settings please check note, 1268821.