Latvia Diamond Perfs

When I bought these, they were described as 'diamond perfs' along the top edge. I'm not sure I know what a diamond perf really is as opposed to the standard round pin and wonder if anyone can give me any advice. The stamps are Latvia Sc 8 perf 11 1/2 all around.

John, it looks like the perfs have been doubled on the top row.

I was wondering if something like that might be the case. They looked like what I would describe as 'sloppy' holes. As if the pins had some play going thru there.

If you look at the perforations on the other 3 sides, they all have very flat tops.
The top row of perforations have a more pointed or volcano shape.
Could be from a loose pin setting.

I almost think they were double perfed with the second set of holes being maybe a millimeter up and to the left. Looking more closely now, a couple of the holes seem to have a little bit of a scallop visible. It always amazes me how many misperfed and multiply-perfed stamps there are from 1918, 1919, and 1920 in Latvia. The stamps I showed above are from a 1919 issue. I guess with the shortage of paper a lot of stuff was let slide thru whatever existed for quality control back then.