Depends on the chocolate type and how much you're eating. Milk chocolate has very low levels (~2mg per 28oz), but dark chocolate is ~15mg per 28oz. Coffee, at 24oz, would be around 275mg, depending.
I find it hard to believe that some folks would feel the caffeine in chocolate unless they ate an entire dark chocolate bar in one sitting, but I suppose it's possible.
I think that 28oz of dark chocolate, whether weight or volume, would be a ludicrous amount to eat in one sitting. A chocolate bar is about 1.5 oz (and 1 fluid ounce of water weighs 1 ounce, at least to a rough approximation), so to eat 28 you'd need to eat nearly 20 chocolate bars.
For that matter 24oz is rather a lot of coffee to drink at once. I brew my daily coffee with 200g of water, or only about 7 floz.
While I realize I'm an outlier, I do NOT consider 24oz of coffee a lot, nor does anyone I know--that's literally a standard coffee cup at a coffee shop these days. At a minimum, I'm drinking 3 pots (~180oz) of coffee a day, with my usual being 3-4x that amount.
So; with that said, while I believe that eating 28oz of chocolate is a lot, I guess it could happen :-)
Wait, on a typical day you're drinking 4-5.5 gallons of coffee? 180oz * 3-4? So 540-720oz?
That's not just an outlier, that's absurd. At 100mg caffeine per 8oz of coffee, that's over 6 grams of coffee per day, or more than 15 times the amount generally considered safe.
But the comment also said "with my usual being 3-4x that amount". I don't know how to square the math in that comment except to interpret it as "180oz is my minimum, my usual is 3-4 times as much as 180oz".
I find it hard to believe that some folks would feel the caffeine in chocolate unless they ate an entire dark chocolate bar in one sitting, but I suppose it's possible.