Parser said
Means by RAW it is impossible to boost a statistic above 12 via leveling. Also, assuming levels are capped at 100 it's also impossible to get above 30 in a given stat even if we're allowed to "bank" points.
Fist off, there is not banking Parameter points. Secondly, it states per level-up. Therefore on any one level up you can invest at most 2 of the 3 points you're given into any one Parameter, and the 3rd into a different one. Or you can invest 1 point each into 3 Parameters. This happens every level-up. This is to make sure that people don't reach the Parameter cap (99) too quickly. Yes on your first level up, a Parameter of 10 can only go up to either 11 or 12, but you can boost that Parameter by 1 or 2 every time you level. So no, it is not impossible to raise a score above 12 purely through leveling.