wow, you are so quick to change gears. When i'm commuting mine are still above yours, but when i am doing some spirited riding mine goes like this:
1st- 0 to 50kmph
2nd-51 to 80kmph
3rd- 81 to 110kmph
4th- 111 to 130kmph
then you can bang it up a couple of gears to drop the revs. For general riding i usually shift around 6-7k rpm and cruise at around 5k minumum. 6th at 56kph seems like it would be lugging a fair bit and you won't see much power until a few seconds after touching the throttle. I sit in 4th at 60kph which is around 5k rpm