Welcome aboard...
In stock trim the bike gets 46 to 50+mpg. What are your expectations here?
I went the other way, added teeth to the rear but the basics are this. Increase the load and the engine compensates by adding fuel when hills are encountered. Thus your net gain is nil as the hills drop the engine vacuum and when fuel is added all you have accomplished is loss of acceleration. To stay in its happy spot it adds fuel....
If you are west of the cascade range its pretty much all hills so I'd leave it alone.
JM2C!