Internal Consistency related to Lehi and Zenos' Allegory -- "Broken off"

There is a subtle internally consistent detail related to Zenos' Allegory in Jacob 5 regarding the expression "broken off," which appears a total of 9 times in the entire Book of Mormon.  Every instance is found on the small plates, and in every case the context is the scattering of Israel.

Lehi uses the expression once in 2 Nephi 3:

5 Wherefore, Joseph truly saw our day. And he obtained a promise of the Lord, that out of the fruit of his loins the Lord God would raise up a righteous branch unto the house of Israel; not the Messiah, but a branch which was to be broken off, nevertheless, to be remembered in the covenants of the Lord that the Messiah should be made manifest unto them in the latter days, in the spirit of power, unto the bringing of them out of darkness unto light—yea, out of hidden darkness and out of captivity unto freedom.

Nephi mentions his father's use of the phrase in 1 Nephi 10:

12 Yea, even my father spake much concerning the Gentiles, and also concerning the house of Israel, that they should be compared like unto an olive tree, whose branches should be broken off and should be scattered upon all the face of the earth.

Nephi also makes mention of this expression while answering his brothers' question about what Lehi meant, 1 Nephi 15:

12 Behold, I say unto you, that the house of Israel was compared unto an olive tree, by the Spirit of the Lord which was in our father; and behold are we not broken off from the house of Israel, and are we not a branch of the house of Israel?

Nephi uses "broken off" twice in 1 Nephi 19:

24 Wherefore I spake unto them, saying: Hear ye the words of the prophet, ye who are a remnant of the house of Israel, a branch who have been broken off; hear ye the words of the prophet, which were written unto all the house of Israel, and liken them unto yourselves, that ye may have hope as well as your brethren from whom ye have been broken off; for after this manner has the prophet written.

Intriguingly, the phrase is found twice in the opening of Nephi's quotation of Isaiah 49 in a sentence which is not found in the Biblical version:

1 And again: Hearken, O ye house of Israel, all ye that are broken off and are driven out because of the wickedness of the pastors of my people; yea, all ye that are broken off, that are scattered abroad, who are of my people, O house of Israel. Listen, O isles, unto me, and hearken ye people from far; the Lord hath called me from the womb; from the bowels of my mother hath he made mention of my name. (1 Nephi 21)

Jacob uses the expression once in his sermon to the Nephites in 2 Nephi 10, in the same verse in which he references God's "will and pleasure" (which is the subject of a previous post on internal consistency related to Zenos' allegory):

22 For behold, the Lord God has led away from time to time from the house of Israel, according to his will and pleasure. And now behold, the Lord remembereth all them who have been broken off, wherefore he remembereth us also.

Finally, we have the last use of the phrase "broken off" in Zenos' allegory:

30 And it came to pass that the Lord of the vineyard and the servant went down into the vineyard; and they came to the tree whose natural branches had been broken off, and the wild branches had been grafted in; and behold all sorts of fruit did cumber the tree. (Jacob 5)

The context is consistent with each usage.  The Lord sees fit to send forth righteous branches of His people prior to the destruction of the main body of the House of Israel in order to preserve a remnant and set up the grand latter-day gathering in of the House of Israel and establishment of His covenant people. The fact that this phrase is uniquely preserved for this context is pretty remarkable.