I just switched from dyno 10w-30 oil to M1 5w-30 this past weekend. Today was the first time I was able to drive it fast on a freeway, and I immediately noticed that the tach was only at 3K RPM at 80 mph. Prior to the switch, 3K RPM only yielded 70 mph. Is this normal? I didn't expect this, but if it helps with my gas economy, it's certainly welcome.