When you create a new league, BLS defaults to a 2-week league. The setting is on the main General Rules tab. It's in "How and When we Bowl" section and is directly below the starting date, season, time, etc. So if it's still set to 2 weeks, your league would only bowl 6 games, hence the 6-game limit. Go back to the General Rules and set that to your season length, and scroll down for additional settings, as the default is Adult/Youth among other settings.
For future posts: Please indicate your version number of BLS-2015 (27.0x.xx) in case there's an issue with a particular version; sometimes a reported issue was addressed in an update that the user had not yet done.
Always check, download, and install the most recent update of your software to ensure that issues may have been corrected.