They apply a scale factor based on time removed from the point where the contest was over, don't they?
Might be that, but plenty of other cases where that hasn't happened.
Depends on total points scored vs the 3,300 as well.
Don't know why I wrote this, it's a pretty vague 'it's the vibe' style answer tbh.
Edit: This is about the ZGL point rise after carking it.