halo 3 campaign achievements?

[ryan r]

i was playing the halo 3 campaign on legendary with my 2 friends. we had 2 skulls tunred on and campaign scoring turned on team. we got like 40,000 points for each level but still no achievement. do i have to play through the level on my own or something?

 

[mr game32]

in order to get the achievement you have to have the amount of points needed to earn the acheivevement by yourself. like if you need 15000 you have to earn 15000 not have a total of 15000.