Page 99: Spend 1 Success icon ot modify the Feat die numerical of your attack by +1 (swords), +2 (bows), +3 (spears) — thus possibly triggering a peircing blow (Sauron and G Rune results unaffected).
So, given that 10 and 12 (G) are your piercing blow dice, and you are carrying a bow, and you roll a 9 on the feat die and get a success overall with an additional 6, you can add +2 for your bow, which would be…..11. It seems silly that you wouldn’t get a piercing blow because piercing blow is defined as 10 or 12.
Can I just assume if you have enough to get at least a 10, your success grants you a piercing blow, almost as if you could choose +1 or +2 for your bow? Common sense dictates you would be rewarded for getting that 9 into piercing territory, but the rule doesn’t make this clear.