Settings during business hours but agents offline

I'd like to display the message for offline status when no agents are online, even if it's during business hours. It seems like if it's during business hours, the messaging widget will initiate a chat rather than the fallback form. After submitting the chat message, the initial message for online will display, then a few seconds the message for offline will display. Also, the default online messages (rather than the custom ones) will be used for both the first and follow-up messages.

How can I set up the widget to use the custom offline messages when agents are offline but it's during business hours?