Khan wasn't an ignorant soldier anymore. He had studied Lieutenant Pouille's books and had learnt many important aspects of the Global Army. His knowledge now involved ranks, levels, and the differences among various groups, so he could understand what it meant to send a whole battalion into the enemy territory.
Ecoruta would belong to the Guko even if the Global Army helped in its conquest. It didn't make much sense to win the war and renegotiate the favorable alliance with the alien species, so large attacks weren't part of HQ's plans.
The decision to send a whole battalion forward described how important the anti-mana project was for the Global Army, and Khan couldn't help but inspect the issue coldly. Forcing a large army to advance through multiple trenches was risky and expensive. HQ was willing to sacrifice many troops as long as the mission succeeded.