I also tuck my pinky when throwing for a strike, and for most spares. When shooting for the 6, 9, or 10 pins I always untuck as it lets me get more of a straighter/controlled line. Like shepp, when the lanes do start to break down, I always attempt either untucking my pinky or shifting my index finger closer to the middle finger. Both help me take a little less hook off the ball, while keeping my normal release.