If I don't have the camera attached, I'd say i get at least 10 minutes. less if I have the camera.
I don't risk it either , so I land once I see the red light blinking. and switch to my 2nd battery... they say it's not good to let the battery drop down below 20% anyhow.
yes, you can change the settings, but do be careful, it's set that way so that you'll have ample juice to return and land. (or for it to automatically land itself when super low on power or for RTH).
Best to stock up on batteries (when they become available that is), than to push the limit of flying time.