I went back and checked the page that connects to the Cybertenko ad that went out Monday morning (with the red graphic removed, thank you!) and the text on it reads as follows: "Monday through Thrusday (sic) each week we will be having items up to 70% OFF for Prime Members and 60% OFF for Non-Prime Members. Be sure to check back each of those days from 4pm to 11:59pm (CST) AND 4 am to 11:59 am (CST)

So, my guess is that today's ad may be supposed to start at 4:00 PM and run to 11:59 PM.