(If total calories and protein are the same, as stated in the post, then carbs must be the same.)
E.g., 2 scoops of Surge is 92 g total, of which 53 g is carbohydrate and 31 g is protein.
Another product cannot put about 53 g of carbs and 31 g of protein into only 1/3 of 92 g, or in other words into only about 31 grams.
The actuality I expect is that it was a mistaken statement that the other product has the same calories with 1/3 the grams of product.
The other product comprises only whey protein, I believe. That is not the case with Surge. The products are intended to serve different purposes. Actually rather than asking what is the difference, the question would be what ingredients are in common? Other than perhaps something like flavoring, the answer would be nothing.