I don't collect Haiti at all, but will try to add some clarification.
Since the excess ink is upside down and backwards from the top of the stamp
No not quite. Not backwards.
I have enclosed the clearest parts of the lettering in boxes, the corresponding areas of original and the extraneous ink.
Here is the clearest part of the extraneous ink area, rotated 180. It reads correctly, thus cannot be from a wet-ink folded-over
I would seek correction, but I suspect these were a rotary press product rather than sheet-fed, and the plates made by a photo-offset technology of some sort. It would be interesting to see addicted's versions to perhaps prove/disprove this as a constant plate variety or a production/handling freak.