You have the highest rep in pro, also finishing 6 laps ahead of second place meant that there was no competition, I'm surprised you didn't lose points which will probably happen as the season goes on. I wouldn't worry about rep too much as it's never a true indicator of how good the manager is. The more races you do in a week the more points you get, so those racing 7 days will always get more points than those only racing 5. If you want to increase your rep that much you need to join a league where your competition has higher rep than you.