The times listed in this recipe are based on my ovens, but not all ovens are created equal.
Time to talk about temperature...
The internal temp of a chuck roast to be fork tender is around 190f (87c). It does not matter if it takes 1 hour, or 1 day… when it hits that temp the collagen melts, and it tenderizes. When it rises above that temp, the heat (like a sponge) squeezes all the water out of the beef and it becomes dry and tough.
The oven temperature of 285f (140c) is a bit lower than most roasts are cooked at; however, the low-and-slow method helps melt the collagen, and makes the roast tender. If you do not have the time, you could raise the temp up to 350f (175c), and this should cut the time almost in half.
Just remember that it is not about time, as much as it is about temperature.
FYI: A good chef's tool to have is an instant-read thermometer