What shaped charges?
The only shaped charges they even had were handheld anti-tank,the only tank loaded shaped charge rounds were interwar experiments that Germany conducted and Italy was the only one who used shaped charge rounds wth artillery,all of which was still an HE round explosion that would be as risky as throwing a grenade at them and praying.
20 meters away is a lot safer in comparison,still risky,but nowhere near as risky as firing directly at the T-34,more so an AP round going clean into the ammo rack,setting off the T-34,and potentialy the truck too.