...S insulin lasting 6 hours taken at the same time you eat a 40 carb breakfast; compared to taking S insulin 1/2 hour before breakfast, is supposed to do this:

S lasting 6 hours taken 1/2 hour before eating; snack is 2 hours later; is supposed to do this:

S lasting 6 hours taken 1/2 hour before eating; snack is 2.5 hours later; is supposed to do this:

S lasting 6 hours taken 1/2 hour before eating; snack is 3.5 hours later; is supposed to do this: