Scoring messed up for Halo 3 last level: Halo

I’ve been playing through the campaigns for both par times and par scores. However, it seems that there is a problem with the last level. The scores between my self and one to three others are added together like they seem to be in every other level and with the level as it is, it is seemingly impossible to get to the par score.

Is anyone else having this problem, or is there a workaround? Thank you.