For example, 'Mech Mortar 1(on TO) is a Cluster Weapon(that has C on its type) but its number is only 1 and there is no column on Cluster Hit Table for 1 - it starts from 2. Swarm Missiles(also on TO) may have the same problem if only one shot is remain.
I assumed that it doesn't roll for the Cluster Hit Table in this case, but is it correct? Nothing on the rules says so.