Qin Tong, Harris, Xiazi, and Quezi all had Ace Mechs, so only ten people needed to use the Mountain-cutting technique.
Looking at it from this perspective, the achievements of the Independent Group need to be taken with a grain of salt, because the original Xinghe Squad had already achieved their goal of all members becoming Ace pilots. This means that today, five Ace Mech Warriors were sacrificed.
Counting the nineteen Aces of the Xinghe Squad, the Federation currently only has forty-three Ace Mech Warriors and one Xinghe Level Mech Warrior.
Such a loss, before the widespread adoption of the Nerve Link Technology, would've been somewhat difficult for the Federation to bear. But now, with the emergence of the newly promoted Ace, Yu Ren, it's not as difficult as before for the Federation to create Ace Mech Warriors.
Therefore, the achievements of the Independent Group are still remarkable.