@superbattleshipyamato123 You are correct, the US should have 17 IPCs. This was covered in the FAQ - which used to be on the Avalon Hill website. Used to be, because Marketing got a wild hair and played 52 pickup with their website. There ought to be a law about leaving information links alone. But there’s not.
A direct link to the current version of the 1941 rule book, with (hopefully) all of the errata folded in, is available at:
https://www.hasbro.com/common/documents/60D52426B94D40B98A9E78EE4DD8BF94/E5D3C8B367B94C70BC0D66E557853387.pdf
The errata does not only change the US IPC level, it adds some needed units to the board - in places like the US Atlantic coast, Moscow, and China. See for yourself.
-Midnight_Reaper
P.S. Found a working deep-link to the FAQ on Avalon’s site, read that first: https://media.wizards.com/2015/downloads/ah/AA_1941_FAQ.pdf