That really doesn't make any goddamn sense. The snares are approximately equal when fighting medium tanks, taking two to damage engines in any realistic scenario, the extra 40 damage being meaningless in almost any case as far as breakpoints are concerned. It's only when you reach premium mediums that there starts to be a difference.
Gren Faust vs KV1140/160 pen) 26%/34% chance to snare in two. 38%/49% (I think?) chance to snare in three, 36%/17% in four.
Generic AT grenade vs Panther100 pen) 13% chance to snare in two. 87% in three.
I'm not sure what stats you are looking at but this is completely wrong. The panther has an extra 160 health and is impossible to snare with two at nades. They do 100 damage and the panther has 960 health, needing 720 to snare. If you want to compare it to something you should compare it to the KV-8, which has the exact same health and front armor. The soviets will always snare the panther in 3 hits, doing 80 damage each time on a deflection. If grens get lucky and penetrate the KV-8 every shot with the faust they can also snare it in three hits, but if they deflect every shot it could potentially take up to SIX.