Are your NPCs assigned as an alias? If so, give the packages to the alias instead.

EDIT This does not solve my issue, so it may not solve yours

So do they just stand perfectly still, or do they walk a bit from time to time?

Check the order and conditions, follow through the wiki again. Certainly sounds like you have a package high up the order that is always meeting its conditions.

Post pictures of the setup and schedule of the daytime package that dominates. Where does it come in your package order.