Ether 1:5 reads as follows: "For behold, I give not the full account, but a part of the account I give, from the tower down until they were destroyed."
With the removal of the third comma, this verse reads differently. With the comma in place, the verse tends to emphasize or imply that the "part" Moroni gives is what is left after not including the other part concerning the creation to the tower see Ether 1:3-4). By removing the comma, the verse now emphasizes the fact that the "part" Moroni was referring to was the information "from the tower down until they were destroyed" which Moroni greatly abridged or "gave not a full account of." Thus, the book of Ether as written by Moroni is truly "an abridgment taken from the Book of Ether" (see Title Page). Moroni confirms this by saying that Ether "finished his record and the hundredth part I [Moroni] have not written" (Ether 15:33). [Alan C. Miner, Personal Notes]