We are now in the 4th competition of this event. By now the various players are all in different stages of the jobs so they will naturally have different amounts of Event Points (EPs) awarded for each task completed. So it is entirely possible for other players to have 250 points within a couple of hours while your possible EPs would be lower, you are further along in the jobs available than they are.
During the event there are 2 types of jobs, one type advanced the story for the event and can be identified by numbers in the job heading, for example, 2/15, Those jobs have a varying number of EPs and Event Keys (EKs) for completing each job. They also are the jobs that advance the % done for the event region.
The other type of jobs appear when you've completed any of the main / numbered story jobs. They are identified by having a "Trash Can" icon next to the contractor's image. These jobs can be discarded and will be replaced by another job. You do not have to be at 100% for these jobs to appear, you only need to complete the entire set of jobs for one contactor.
One thing about these jobs is that they are all have the same EPs and EKs. While the EPs remain fixed from then all, the EKs may decline over time, usually reducing by 5 as you gain more overall EPs in the event.