Redirect referrer spam, without awstats counting it as visit

Hello, I am trying to limit referrer spam from urls that look like the first line below. The referrals I am interested in are mostly like the second line:
http://referralspam.ru http://www.domain.com/viewtopic.php
My site is on a shared hosting account, so my tools are limited to mod_rewrite in the htaccess file. I tried adding the following mod-rewrite rule to catch any referrer url with http//(anything except '/').(1-4 alphabetic chars, may be followed by '/'):
RewriteCond %{HTTP_REFERER} ^http://[^/]*\.[a-zA-Z]{1,4}/?$ [NC] RewriteRule .* /system/services/referrer/filter.php?ref=%{HTTP_REFERER} [L]
The filter.php file records the referrer information in a log file, so I can check if any legitimate request might have been caught. I can then modify the htaccess rules to make the necessary corrections. The file also displays a page with an apology, and a button that the visitor can press to enter the site. I have a couple of issues though, which I was hoping to get some advice on. Is there a way to redirect referrer spam, and log it, in such a way that Awstats will not count it as a visitor? Also, the mod_rewrite rule does not seem to be catching anything. I still see the same types of referrals in my Awstats, and my log file stays empty. However after testing my rule from a Google link, it worked fine, including logging the referrer (I changed my rule to detect 'https', then changed it back):
2016-01-06 21:36:29 Referrer redirected by htaccess: https://www.google.com
Here is the code for my filter.php:
."/../system/services/referrer/filter.inc"); ?>

."/../system/services/referrer/"); define ('LOGFILE', HOME_FOLDER.'referrer.log'); $backgrImg = "/system/services/referrer/g3sf15.gif"; $textColorNormal = "#ffd700"; $link = "http://www.mywebsite.com"; if(isset($_GET['ref">)) { $referrer = "Referrer redirected by htaccess: ".strip_tags(trim($_GET['ref">)); } else if(isset($_SERVER['HTTP_REFERER">)){ $referrer = "Referrer not redirected by htaccess: ".strip_tags(trim($_SERVER['HTTP_REFERER">)); } else{ $referrer = "Direct access from: ".strip_tags(trim($_SERVER['REMOTE_ADDR">)); } $time = date('Y-m-d H:i:s', $_SERVER['REQUEST_TIME">); $str = $time." ".$referrer.PHP_EOL; error_log($str, 3, LOGFILE); // append to log ?> Referral filter

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UPDATE: I cought a little bugger!
2016-01-06 21:51:06 Referrer redirected by htaccess: http://vesta-lada.net/ 2016-01-06 21:51:06 Referrer redirected by htaccess: http://vesta-lada.net/ 2016-01-06 21:51:07 Referrer redirected by htaccess: http://vesta-lada.net/
Not quite sure when it started to work, but I remember the last thing that was added to the mod_rewrite rule was the ending "/?". However, these visits are still recorded in Awstats 'Links from an external page'. Are they counted in the stats for unique visitor? If so, I guess the original question still remains. Is there anything I can tweak in the Awstats configuration file? I have an awstats.mydomain.conf file in folder home/tmp/awstats. It crossed my mind to change the rewrite rule to 'Fail, but redirect to this page first':
RewriteRule .* /system/services/referrer/filter.php?ref=%{HTTP_REFERER} [F, L]
It seemed like too dumb of an idea to even try. UPDATE: Apologies I was not sure if this should be posted as a different question. The variable %{HTTP_REFERER} can return two different strings for the same domain:
http://www.domain_name.com http://domain_name.com
Why the difference? Thanks!