All offer emails go out during 7AM-10PM.
Sign up offer: Any customers that sign up to your marketing program past 10 PM will receive their offer email the next morning
Birthday offer: Customers will receive their birthday offer first thing in the morning and it expires at midnight the same day
Promotional offer: Once you set a promotional offer - it goes out the next calendar day
Custom offer: If the custom offer is set in the 7 AM - 10 PM window, then the offer goes out immediately. If not, then it goes out the next morning