This question already has an answer here:
I have read many times that by saving up 1M credits and buying one tier of achievements and then loading, then buying other tier and so on lets you have the master mechanic achievement.
I came across this answer:
"As of now, the best way to earn the armory achievements is to play the campaign multiple times, selecting different upgrades on each playthrough, as achievements are shared across all campaigns."
I am confused. I am in the middle of the campaign and I don't want to waste time. So by doing this can I still get the achievement? Or need I play the campaign one other time ?