You're right. I disabled the bonus in the book (update book 6). Or maybe "0 + 3" should be considered as "10 + 3" (in combat 0 == 10 but every value > 10 is considered 10).
if at any time you should pick a 0 from the Random Number Table when using the bow, the Jakan will break.
The text does not say that you cannot use your mindblast/psi-surge discipline. I'm not sure it is actually correct to disable them.