Yeah, we get into analyzing the minute details and while qualitatively there are differences, in real-world results of quantitative measurements, the actual differences are very, very minor. If you can devise a proper double-blind test to compare 28 vs. 23c tyres, you'll find that there's very little difference in performance. Even then, it's gonna have to be at the upper-ends of speeds, such as in all-out racing conditions or TTs and the differences will be a matter of seconds per hour or just a meter or two per kilometer.