Without spears they will always have one rank of supporting attacks, so in a 5 by 5 unit that would be 15 attacks.
With spears charging they would have the same; one rank of supporting attacks. When they have not charged they will get two ranks of supporting attacks, so that 5 by 5 unit would get 20 attacks total.
When in a horde they would both gain an additional rank of attacks; two ranks of supporting for HW+Shield and charging spears, and three ranks of supporting attackc for spears that have not just charged.