Hi Kawada,
Yes, This appears to be a documentation issue and the loop that you have highlighted in your first post is the right way to implement the multipass. If you look at the earlier example in the document of N=1024 and radix =4 with 4 passes and compared it to the second example N = 2048 and radix = 2, with 16 passes and it does appear to be a typo in the for loop.
This is unfortunately a very old doc so it may take some time to get updated. Thanks for your patience and to point this out. We hope that this post will help other community members aware of the issue until this issue is fixed in the docs.
Regards,
Rahul