As said above.

In addition to all of that, you really do NOT want to push a battery pack more than you have to.

Ideally it would be advantageous to configure a plane so that you draw well below the C rating of the battery at say 80% throttle when this represents normal flight modes.

This will conserve the lifetime of the battery, but still give you a reserve.

Remember however that increasing the "C" rating does not equate to longer flight times.

If you want longer flight times, increase the mAh rating of the battery, which BTW also increases it's "C" rating too.

In your application a 25C 1300mAh battery will last just as long as a 15C 1300mAh battery.