1. This is true if you are careful about giving them stat-boosting food at every level during the leveling process.

…and…

  1. The stat boost they get is a total of about 4.2 stat points. Not 4.2 point per stat, but total.

Let’s say you give a berserker steaks while you’re leveling them up. If they have the +14% chance to get a strength point every time they level, all 20 times, then they will get an average of 4.2 more strength points than a berserker that you don’t give food while they’re leveling.

However (as was pointed out above) that’s still subject to RNG. You might have one berserker who levels 20 times with a 80%+14% chance to get more strength points, and a different berserker who levels 20 times with a 70%+14% chance to get more strength points, and the berserker with the 70%+14% chance ends up getting more strength points at Lvl 20. It’s just like rolling dice, you are not guaranteed to get the result you’re hoping for. The odds are in favor of the berserker with the 80%+14% chance, but it’s not guaranteed.

If you’re bothered by the idea that your thrall might have gotten a couple of extra stat points by leveling normally, rather than getting 12 levels from a single purge, I wouldn’t worry about it. The difference between manually leveleing and automax levling is small.