Amonhi’s response if very good, and right on point. There is an implication for the presentation in the book. In a quick search for “sin” and “transgression” I found:

Mosiah 3: 11 For behold, and also his blood atoneth for the sins of those who have fallen by the transgression of Adam, who have died not knowing the will of God concerning them, or who have ignorantly sinned.

This seems to counter the claim made in the book. Amonhi suggests that these two words are not always used precisely by authors/translators of the scripture. Thus, Amonhi’s discussion of the need to infer from context whether it is actually sin or transgression being discussed should probably be in the book.

I know it would be cumbersome, but in the book it might make sense to choose words that would not conflict with the scriptures. For example, use “accountable sin” for those actions where we have sufficient knowledge, etc. to be accountable. Use sin/transgression for the others. Then, you would be completely consistent with scripture.