Got the penetrator perk up to level 2. Is it just me? Or is the perk just... useless?

Its true, the VATS percentages do not decrease at lvl2 when enemies hide behind cover... But whenever i fire during VATs, the bullets do not penetrate the walls.. :0 Bullets just hit the wall and the enemy receives no HP damage..

I dunno if:

1) The cover walls are too thick so bullets dont go thru despite the penetrator perk; or

2) Only specific bullet/ammo types can penetrate; or

3) The penetrator perk is really just a perk that increases VATS success percentages, & there's no such thing as bullets bypassing walls in this game.

If #3 is the case, then im hoping it gets fixed (make them REALLY "penetrate") via patch because its a useless perk if this is the case.