Schedule Prioritization:
Suppose you have three categories with Requeue posts all set to post at the same time. How does the software decide the order of posting?
The software prioritizes based on the order you schedule the posts. If you have a single Schedule item with all three categories enabled, it will send the first one you schedule and push the next two to later times.
However, if you add three separate Schedule items for the same time (for example, 3 pm), each with a different category enabled, the software will post all three posts simultaneously.