Settting Expires/Cache-Control Headers buggy

[basos]

Hello,
I am a customer to a company that is running lightspeed.
I am trying to configure Expires/Cache Control Headers. It seems in some file types there are some default rules that are added to my .htaccess provided rules.

I will post two cases for reference.
One html file that is working as expected (no Expires/Cache-Control Headers by default, the .htaccess rules are applied correctly) and another with a js file that the bug is manifested ( default Expires/Cache-Control Headers do exist, the .htaccess rules are mixed with the default).

HTML FILE
==========
## FIRST EXPIRES (AND MAX AGE)
<IfModule mod_expires.c>
ExpiresActive On
ExpiresDefault "access plus 120 seconds"
</IfModule>

## THEN CACHE CONTROL FOR FINER CONTROL
Header Set Cache-Control "must-revalidate"


RESPONSE HEADERS
---------------
Accept-Ranges: bytes
Cache-Control: must-revalidate, max-age=120
Connection: close
Content-Encoding: gzip
Content-Length: 4949
Content-Type: text/html
Date: Thu, 10 May 2012 11:02:28 GMT
Etag: "42e8-4fa957f7-0"
Expires: Thu, 10 May 2012 11:04:28 GMT
Last-Modified: Tue, 08 May 2012 17:29:27 GMT
Server: LiteSpeed
Vary: Accept-Encoding




JS FILE (BUGGY)
========

<FilesMatch "\.(js)$">
Header Set Expires "Thu, 10 May 2012 00:00:01 GMT"
Header Set Cache-Control "no-cache, must-revalidate"
</FilesMatch>


RESPONSE HEADERS
--------------------
Accept-Ranges: bytes
Cache-Control: no-cache, must-revalidate, max-age=604800 <====== MIXED
Connection: close
Content-Encoding: gzip
Content-Length: 319
Content-Type: application/javascript
Date: Thu, 10 May 2012 11:05:26 GMT
Etag: "1d0-4fab9b48-0"
Expires: Thu, 10 May 2012 00:00:01 GMT, Thu, 17 May 2012 11:05:26 GMT <== MIXED
Last-Modified: Thu, 10 May 2012 10:41:12 GMT
Server: LiteSpeed
Vary: Accept-Encoding