Maybe your web host requires that the .htaccess file has 404 file permissions. On some web hosts that is mandatory and automated. On other hosts they do not allow 404 file permissions and then you have all the inbetweens with all the other web hosts.
Some web hosts require that you have both a BPS Root and BPS wp-admin htaccess file in order for things to work correctly. On other hosts that is not required. In any case, if you use the default generic WordPress root htaccess code/file then a wp-admin htaccess file would not be needed for any host.