Okay, as implemented in the rules, this quality is pretty useless. The only mentions of it are for a Feral Worlder ability that grants Proven 3 to low-tech weapons, and Krak Missiles with Proven 2. How much extra damage is actually being added by this quality? In the case of Proven 2, there is only an average damage increase of 0.1, from 5.5 to 5.6. For Proven 3, the increase to damage is 0.3, from 5.5 to 5.8. This isn't even increasing average damage by 1 point, and the Tearing quality, by comparison, increases damage by 1.65 points, AND almost doubles the chance of getting a critical hit. All that the Proven quality does is increase the average damage of an attack, while not actually increasing its maximum damage. Not until Proven 7, when Proven adds 2 to the average damage, is the damage increase from Tearing even met or exceeded.
So what should be done for this quality? I'd suggest turning Proven 2 into Proven 7, and Proven 3 into Proven 8 (Proven 8 increases damage by 2.6)