So, I guess that's the long version of saying I agree with Frank. Your arrow had to have been wibbly wobbly at 20 yards but finally stabilized when it got to 30 for there to have been better penetration at 30.
Very possible! I just grabbed a handfull of alluminums to screw around. My bow wasn't tuned to them at all. Although they appeared to be hitting the target straight you guys are probably correct. I guess it shows the importance of tuning your bow to your arrows , especially for hunting penetration.