Here is an example of a flaw within a single letter, this time on the first R in the cancel. These stamps were used only days apart, showing no longevity or persistence to the flaw, but the location and similarity of the flaw makes it clear that each of these stamps came from the same position on the cancelling plate.
JUN 21 1902
JUN 3 - 1902
I doubt whether this flaw or variety would deserve its own listing.