TCBH is applicable to each Trunk Route, typically BHCC will apply to the capability of the equipment to switch ALL calls (internal, extension to trunk and trunk-trunk)
Traffic capabilities will depend upon PABX model, software issue and trunk route capacities.
Perhaps more relevant is the switchinh matrix of the PBX, is it ‘blocking’ or ‘non-blocking’?
ie, is it possible the call will fail due to insufficient capacity of the switch matrix.