access control with time

I'm gonna restrict user's web-surfing on work time.

squid.conf:
 acl security dstdomain unwanted.site.com
 acl beforenoon time MTWHFA 08:30-12:30
 acl afternoon time MTWHF 13:30-18:00
 http_access deny security beforenoon afternoon
 http_access allow all

It does not worked as I intended.
What's wrong?

Are acl lists after http_access allow/deny and'ed or or'ed?
Is time acl is base on local or global time?

-- 
\|/ ____ \|/     Brutal Truth - Extreme Conditions Demand Extreme Reponses
 @~/ oO \~@            Office : +82-336-630-2147,2448  FAX: 2113
/_( \__/ )_\            EMail : seojs@sysic.hei.co.kr
   \__U_/      HiTEL/Shinbiro : LionMane
 __/    \__          Cellular : 017-227-2795