Hi again, Chris,
I have just done some checking, and found another odd anomaly. The new cousin was added to one spouse! Thing is, I have her LNAB as UNKNOWN, CLN as Allison. Could the UNKNOWN be a hint as to why the other birth names don't seem to get added? She is: E. Vonee (UNKNOWN) Allison.
Here's the list of what the tool did, with the cousin's name omitted:
Added [omitted] to Trusted List of Allison-588.
Added [omitted] to Trusted List of Allison-550.
Added [omitted] to Trusted List of UNKNOWN-149873.
Added [omitted] to Trusted List of Allison-585.
Added [omitted] to Trusted List of Allison-579.
Added [omitted] to Trusted List of Allison-582.
Added [omitted] to Trusted List of Allison-584.
Added [omitted] to Trusted List of Allison-552.
Added [omitted] to Trusted List of Allison-553.
Added [omitted] to Trusted List of Allison-587.
Added [omitted] to Trusted List of Allison-647.
Added [omitted] to Trusted List of Allison-581.
Added [omitted] to Trusted List of Allison-577.
Added [omitted] to Trusted List of Allison-586.
Added [omitted] to Trusted List of Allison-580.
Added [omitted] to Trusted List of Allison-583.
Added [omitted] to Trusted List of Allison-578.
Added [omitted] to Trusted List of Allison-551.
Incidentally (and a little off topic), I believe I know UNKNOWN-149873's correct LNAB. I never entered it because it's a bit circumstantial, with no real proof it's correct.