For planetside its kind of incomparable to our servers. They have different servers running different 'parts' of the territories and don't think single server handled 1,158 players at once.
I would guess the way its meant is the peak of online players at given time. So basically if you sumed counted of players on each server in total for paintball.
PS:No idea about our top peak, but i would guess around 100 players back in days.