non-canonical permalinks

Greetings,
I don’t quite understand how the WordPress 4.0.2 handles permalinks’ requests.

I understand the rule of .htaccess, mind you, but what I don’t understand is how it determines either that:

case1: The request is a permalink so it displays the single_post page along with comments (in my setting), or

case2: that although the request was redirected internally to the URI parameters identifying the post, the request is not The Permalink and as such the post is displayed but not in a single_post fashion, and with no comments; as if in an archive page.

I discovered also that unless the rewrite in .htaccess is an external redirect (either 301 or 302), the client gets a 404 status, while in fact the page displayed contains the post!

I use verbose rules by setting:

var $use_verbose_rules = true

in class WP_Rewrite in classes.php because I have rules in my .htaccess that receive redirects from my blog at Blogspot and tries to redirect them to WP. Like this:

RewriteRule ^atom.xml /atom/ [NC,R=301,QSA,L]
RewriteRule ^([0-9]{4})_([0-9]{1,2})_[0-9]{1,2}(_zamakan)?_archive.html? /$1/$2/ [NC,R=301,L]
RewriteRule ^([0-9]{4})/([0-9]{1,2})/(.+).html? /index.php?year=$1&monthnum=$2&name=$3 [NC,L]

and my permalink structure is:

/%year%/%monthnum%/%day%/%hour%%minute%%second%


try for example http://zamakan.gharbeia.org/2005/04/blog-post_26.html
which leads to the correct post but with a 404 error, unless I set the third rule above to:

RewriteRule ^([0-9]{4})/([0-9]{1,2})/(.+).html? /index.php?year=$1&monthnum=$2&name=$3 [NC,R,L]

then it works by redirecting to http://zamakan.gharbeia.org/index.php?year=2005&monthnum=04&name=blog-post_26