When companies market their aero gear, they make claims like, "60 seconds faster over 40km going 25mph when compared to non-aero gear," or something to that effect.

Using this example, my question is, if you wear the aero gear and go slower than 25mph, will you save more or less than 60 seconds? Intuitively, most people would say that the faster you go, the more aero savings you'll have. So if you go slower than 25mph, you'll save less than 60 seconds. But I've also read the opposite.

Does anyone ACTUALLY KNOW the answer. Gut feelings or guesses aren't going to help here. Thanks so much!