Why don't you just use the browser dev console to check the page load time? It will tell you everything you need to know without moving to an external tool. In chrome go to the network tab.
Not sure why it's not reduced but I suspect that the 1.82s load time for 15mb page size was incorrect. Also, if I'm wrong about my previous sentence, then the 0.03s discrepancy would most likely just be an acceptable delta. Doing a multitude of load times on different browsers on different networks would help you understand your page load.