Jon: I didn't mean to give the impression of any expertise I don't actually have. My experience in programming was long ago. (It was mostly in COBOL, in fact.) It gave me some appreciation of the complexities of programming, but I am far from being able to fix the current problem. I only meant to point out that some information seems to exist in the index about how the messages were originally numbered. How to extract that information and use it, is totally beyond my experience. There might not be a practical way—or any way—to do it. I was hoping someone else could figure something out.

Meanwhile, here are some more observations that I hope will be useful to someone:

Even some very old messages appear out of sequence, and seem to have been renumbered. It isn't just the messages since December, 2004.

See this thread for instance: Lyr Req: You're a Rascal, Tarry Flynn.

There are 20 messages. Only the last message is recent; all the other postings are from 1999.

If you number the messages according to their age, they appear in this order:
19, 2, 1, 12, 13, 3, 4, 5, 6, 7, 8, 9, 10, 11, 14, 18, 15, 17, 16, 20.
That means the oldest message appears in position 3, the second oldest in position 2, the third oldest in position 6, etc. In other words, they are quite scrambled.