...that one ounce shotshell is loaded over 1/16th of an ounce light? 

...that 9 pellet 00B round is shy a pellet?


                                               

According to the Sporting Arms and Manufacturers Institute these are among the voluntary "Standard Industry Tolerances" for shotshells. 

See the * marked standards on the following list for the "In Spec" tolerances mentioned in the first post.

https://saami.org/wp-content/uploads/2019/06/ANSI-SAAMI-Z299.2-Shotshell-2015-R2019-Approved-2019-04-23.pdf

Page 46:

I. Shot Weight per Shell
a. Game Loads +4% -7% *
b. Target Loads +3% -5%

II. Pellet Count per Ounce
a. Nominal ±10%

III. Buck Shot Pellet Count per Shell
a. 0 and 00 Nominal -1 pellet      *
b. 1 and smaller Nominal -2 pellets

IV. Diameter
a. Game Shot Nominal ±0.010” (0.25 mm)
b. Target Shot Nominal ±0.005” (0.13 mm)
c. Buck Shot Nominal ±0.015” (0.38 mm)