The bouncing rounds off the ground was mostly by luck. It wasn't a skill, you fire at the tank and some will hit the ground below and maybe ricochet off. Lucky deflection but it's your kill, if you're willing to go against a Panther firing a 12.7mm MG back up at you, you deserve the praise.
Especially in 1944 when they had the Wirbelwind that beautifully crafter Quad-20mm Mobile AA Gun.