I'm afraid that the methods and intentions of the Church of Latter Day Saints and its members are not really within my area of knowledge. Nor can I explain the difference in content of the batches.
The submitted batch has
Mary CHRISTIAN (of Robert and Mary) 31 Oct 1773
the extracted batch has
Mary CHRISTIAN (of Robert and Mary) 31 Dec 1775
While both may be true baptisms, I can't see why they are not in both batches.
I normally have a couple of days in April each year at Lincoln Archives.