This subtle change in the ending time, which even escaped detection by you,
Nb4powerup, had a meaningful impact on my account. I crowned one plane upgrade at 7:25 Central Time, with the intent of starting another at the sale price. That's when I discovered the sale had ended, and the fighter plane upgrade was back to full price (160k oil in my case). Making up 80k oil is no small task, so I basically missed out on one level of planes, and wasted 500 crowns in the process. That's very frustrating. Of course customer support is not interested in how it impacted me - the only response they have is "The sale ended on time, as scheduled". Yes, thank you for that revelation. I kinda figured that out right after I dumped the crowns.
Pretty much every sale has started on Thursday and ended on Monday at 14:00 UTC - people get accustomed to that timetable. If you are going to change that, one obvious sentence in the text of the splash screen announcement would be tremendously helpful to the players, something like "THIS IS TWO HOURS EARLIER THAN THE NORMAL END TIME"
I've been a long time player (1.5 years) and forum watcher, but this is the first time I've posted here. Probably in the wrong place too, as it appears nobody official reads these threads after they go up.