A 300 attack grade Rocket launcher compared to a 267 grade rocket launcher, of exactly the same base stats, the 300 will be better. A 300 grade auto rifle compared to a 267 rocket launcher, the rocket launcher will deal more damage, even though its attack is lower. You will need to compare same group weapons together, auto rifles, scout rifles etc.
And you have not wasted energy uprating your weapon to 300, especially if you use it a lot.
As for Atheons battle, the relic holder doesn't need to engage in attacking him. What I was recommending to do was jump down to the center plinth, put up a shield from the relic, then the remaining five could unleash attacks on atheon, the 3 in the away team, just before he calls his time thing, would move to the back, get teleported, while the others keep the plate open, we come back in, jump on the centre plinth again, put up the relic sheild, rinse and repeat.
What we were doing was not getting to the centre quick enough as a unit, or the home team were leaving supplicants floating around which were taking out the away team on their arrival, or the relic holder cleansing too often or not enough, or dieing too quickly, or losing communication, or not have adequate weapons for the individual roles, or a few other things. When we iron these out we will do the whole thing in an hour and a half, not just the atheon Battle.