Symone performance - speed/consumption

This is my first ever mototcycle, as I stated before in previous posts, so I've no terms of comparison.

Now what I can say is that I'm very satisfied with it, but... I trully sense that some other maxi-scooter are way better in terms of motor (speed/performance/consumption).

I've been talking to other maxi-scooter owners and they say that their machines spend less gas than mine.
I'm doing 1 deposit (12lts) to make ~280kms which gives more than 4,2lts/100km :(
I know that I'm a heavy guy, and that I don't perform a conservative drive (I speed up downhill a lot) but at this time I really thought that it would have a better consumption... :(

On the way home I always do this big hill on the highway and other 125 scooters always pass me by... all other brands seem to have more "power", even 125 with two people on it :(

Yesterday was the first time EVER I've pass a scooter on the hill... It was a guy bigger that me with an Sym GTS 125 Evo just like my Symone :)