Good question. And I’ll reference the study you posted as well as the skratch article I posted.
It is now well recognized that solutions with a carbohydrate content of ≤2.5% empty from the stomach at essentially the same rate as that of equal volumes of water,47 and most studies have shown that carbohydrate levels ≥6% unequivocally slow emptying.
The short answer to the first question is that our Sport Hydration Drink Mix is only 80 Calories per serving because it is our experience that a 4% carbohydrate solution
Depending on one’s hydration state, blood osmolality can range anywhere from 275 to 295 mOsmol per kg of water. Our Sport Hydration Drink Mix has an osmolality of 160 mOsmol per kg of water, primarily because of the lower concentration of carbohydrate that we use and the absence of excess ingredients like coloring agents, flavoring agents, preservatives, and emulsifiers."
We can’t disprove things by going to a ridiculous extent, ie “perfectly matched”. It’s also not a 0 or 1. Those quotes express what we should aim for. Our discussion started because folks were talking about increasing their hourly carb intake. I expressed that it needs to be matched with extra water. Just increasing carbs trends you in the wrong direction. Any additional water trends you in a better direction. So I can’t say you are doing it wrong if you don’t get down to exactly 4-6%. And that’s not what I said. I just said that an increase in carbs needs matched with some water.