Having trouble with time of day

Hey, just started messing with this yesterday and im having trouble with the time of day changes. I have done changes based on the sunrise/sunset but the sunset is typically too early. Specifically im trying to have objects change between 10pm and 6am.

I have tried a bunch of different strings using the DH and Dk tags and they just wont work. They are either not showing up entirely or they show up to the opposite (which i would need for the daytime settings). the closest ive gotten is they will show up at 9 or 10 pm but disappear once it hits midnight.