Block perfing

I think that you are perfectly right, Mr Bear. In fact, Italian stamps of the era are invariably perf 14, all of two possible sizes and with few variations in perfs and or size.

Excellent point about the corner perfs.
The correct terms to use though, I believe, would be line, comb, and block.

line -- when perfs are run horizontally, then vertically (or vise-verse) resulting in corner perfs nearly always misaligned.

comb -- when three sides are perfed in block fashion(for example two sides and the bottom), then the next row up is perfed likewise. Usually all perfs end up aligned perfectly.
:....:....:   <-----comb(imagine more vertical dots)

block -- when a whole pane or sheet is perfed at once, and all are for sure aligned perfectly.