The timer on the value pack ends when the event ends for all players. Meaning those who started later or allowed the storybook to autostart.
Still, I wish S8 would do something for those players who got stuck no matter how much they played or payed! Deliberately programming low to non-existent drops for onyx petals and placing 2 neighbor requests near the end (again) was dirty enough, but the glitches where the goals refused to unlock or re-locked after the fact caused holdups that players had zero control over. (Thinking of those little vials of nectar!)