I'm wondering how this works? I recently unlocked the level 40 mission and my advisor says "I'll be blunt, the squadron isn't ready for this mission.". So I start using my 3 trainings per day thinking it'll raise my squad's stats high enough to eventually be able to beat the mission, but all the trainings do is reallocate my existing stats and not actually increase my overall power. So how am I supposed to beat the level 40 mission? I must be missing something here, can someone please explain how this works?

Thanks!