i am on Firefox and can not run the packet loss test on pingtest.net due to the security issues with java
but when i do run the ping test i always get a B* due to the fact that i can not run the packet loss test
but in the past when i would run the packet loss test on pingtest.net (back when java and Firefox had no issues) i would always get a A* rating with the same ping and jitter results that you are receiving
so i think that because the test could not run the packet loss test it by default gives you a rating less then a A based on your ping and jitter
also isn't your area supposed to be 150mbps down and 20mbps up?