Benjamin Franklin 15c

I have not studied such stamps with perforation, I studied stamps with perforation which I publish from 1909-1928

Or a #437 stamp with jumbo margins vs. a #437 with narrow margins?

I blame Larry Weiss for publishing the 'counting trick' back in 1984.
Don

The "counting trick" works, IF one has many years of experience looking at stamps. It is a very advanced "trick", not meant for novices.

I think the only thing happening here is OP's translation service is not able to distinguish between "perforation 10" and "10 perforations." It's a subtlety in English (and every language, natively) but isn't being interpreted by the software.
I noticed a similar problem in another of OP's threads, when he translated an issue as having been printed on only "100 sheets," and NSK had to tell him that the issue had been printed countless times on "sheets of 100."

I blame Larry Weiss for publishing the 'counting trick' back in 1984.
Don

Yes I had a run-in with Larry Weiss around that time because I didn't believe him...
I was rather a newbie then :-)

You don't need to "study such stamps" to determine the perforation rate. You simply use a perforation gauge.

So, the question is how would you determine the perforation rate of the stamp I posted above?