Black Coffee

I'm trying to sort out the Poirots on my shelf, and I'm confused by the CK information for Black Coffee. It says that it was first published in 1961 and is the 33rd Hercule Poirot novel. Every other source says it was first published in 1998 and based off a 1930 play, so it should either be #7, right before Peril at End House, or at the end of the series (or not in the series at all, depending on how purist you are.) In which case, does the books after #32 (The Adventure of the Christmas Pudding and a Selection of Entrees) move up, or does something else belong to the #33 slot? Is there a standard numbering, or is this just what fell out when they were placed into order for LibraryThing?

The play is from 1930. The novel is from 1998 and is technically written by Charles Osborne based on the play from Agatha Christie.

When Harper Collins published all of the books a few years ago, they put it at #7. So up to you really - either put it between The Mystery of the Blue Train and Peril at End House or at the end of the line...

PS: The Christmas pudding is #32 if you count all the short story collections also (and it is a short story collection after all)... so you have enough behind it (The Clocks, Third Girl, Hallowe'en Party, Elephants Can Remember, Poirot's Early Cases and Curtain: Poirot's Last Case. There is no moving of numbers... :)