It is certainly possible that a mistake was made in the cataloging, but I don't know. I can't pretend to always understand the old scheme they used when filming. I only know that when there is more than one "v" number (which I think stands for "volume"), then there is more than one section on the film for the records of that time period. That makes sense for the records such as the births they list for 1846-1880: this has two "v" numbers and we see from AO that this range is originally covered by two separate church books, one from 1846-1858 and one from 1859-1880. So it makes sense that there would be two sections on the film.
Since the other site seems to indicate that the til-/afgangsliste are in their own separate book, perhaps the LDS filmers just decided to add that book on the end of film 48831 and then continue with the other books for 1846-1880 on the next film 48832. Why they chose to put the entirety of the 1830-1876 TA lists into one catalog entry, I don't know. But the two "v" numbers (6 & 1) indicate to me that there are two separate sections on the film.
Of course, this may not make much difference to Ian if he is not going to use the LDS microfilm. But I guess whoever looks at the records should be forewarned that the scanned images of the 1846-1876 in-and-out lists may not be exactly where one would expect to find them!