The Gemini links are dead this morning (I'm in the UK) so for anyone trying to follow this, here's the Songwrite file (extracted on this Android device):

N-An Acre of Land
C-
A-
T-
S-100
K-F
B-6/8
F-
H-
M-5R-2 R-8 a-8 F-4 F-8 F-4 a-0 a-0 F-9 F-0 F-8 F-5 c-5 c-4 b-8 a-4 b-8 c-4 c-8
L-                           My  fa-     ther left   me an a-  cre of land,      I-         vy,      sing  i-    ve-  ry,     My
H-
M-5d-4 d-8 b-8 c-8 d-8 c-8 d-8 b-8 a-5 F-4 G-8 a-8 b-8 a-8 a-8 G-8 F-8 D-4 E-8 F-4 R-8 R-5
L-       fa-    ther  left me an  a- cre of   land,      And    a    bunch of green ho;-ly and i-      ve- ry.
H-
M-5R-3 R-3 R-3 R-3 R-3
L-

It's longer than the ABC posted above. It looks like the same tune as the link I posted in abcnotation.com - it starts A F F F A which the ABC doesn't.

Curiously, the Acre of Land in the FolkInfo database (see this recent thread, which I thought was derived from DT, is different:
https://folkinfo.mainlynorfolk.info/songs/19.html

I suggest that for the conversion to be deemed successful all parts of the Songwrite file must be correctly included in the ABC.