You can plod about on a fazer 600 and get high figures too. I got a recorded 72.9 mpg once over 100 mile range riding like a nun, check out my fuelly app at the bottom of this post.
If it's any consolation, my current work bike is a bandit 600, and it barely hits 45 mpg! I was gutted, as my last fazer 600 did an average of 54mpg. You've been spoilt by the very frugal, but boring v twin!