I think the "Journey CUM Reservation ticket after chart preparation" means ticket booked from current counter past chart preparation (seems BCT-RTM part would have AVL berth).
The train surely dont have CNF berth for BCT-NZM leg & hence max distance (RTM) was booked (as AVL Current berth), while next leg was proportioned with WL which have high chance of clearance or on board, TTE would find some berth...