Muesli

Muesli is mostly whole grains, if I'm not mistaken. Unless you REALLY chew it well it's pretty difficult for your body to access the carbs inside the seed coats. This is why the 2 hr number will be higher, too. As the seeds progress further thru the GI tract our body's break down more of the cellulose layer to access the seed interior. This is the idea behind whole grain (as in whole seed) foods for diabetics. Plus the added fiber makes the seeds move more quickly thru the GI tract so the body has less time to grab nutrients.

White bread, on the other hand has just the wheat seed's interior that has been ground and processed through kneading and rising so it's extra digestible. Each little molecule of flour is all ready to mix with gastric juices and be converted to glucose where it just slips through the intestinal wall and into the blood. If you took a handful of wheat, exactly the amount that it takes to make a slice of bread, and chewed and ate it you would get your mueslix results.

Although the carb count for bread and muesli may be the same, the actual carbs presented to the intestinal wall are very different. If you were to mix your muesli with water and cook it in the microwave like oatmeal you would have the same grains present, but in a much more digestible form and there would probably be higher numbers to show for it. Try it and see.