What I meant by glancing blow is to much from the outside in, or inside out, or steep angle of attack. If you feel like your upright and want to fatten out just stand a little further from the ball. If you hit a drive that imparts to much "slice" spin or Hook "spin" (Notice I didnt use fade or draw) your definetly going to loose distance. Does your ball ever balloon in midflight. if your swing to steep with the driver too much back spin is a distance killer...

Nick