[squid-users] Problem refreshing cache. Eating all of my Bandwidth.

Im using squid 2.9 Stable 9 behind my E3 and my local network.
Recently, i used some rules to cache windows updates to save
bandwidth. In the morning-Afternoon, the clients are "Hits" from my
cache, but around 6/7pm, my squid appear to be refreshing all my cache.

these are my rules:

refresh_pattern windowsupdate.com/.*\.(cab|exe|dll) 10080 80% 100800
reload-into-ims
refresh_pattern windowsupdate.microsoft.com/.*\.(cab|exe|dll) 10080
80% 100800 reload-into-ims
refresh_pattern download.microsoft.com/.*\.(cab|exe|dll) 10080 80%
100800 reload-into-ims
refresh_pattern au.download.windowsupdate.com/.*\.(cab|exe|dll) 10080
80% 100800 reload-into-ims
refresh_pattern symantecliveupdate.com/.*\.(zip|exe) 10080 500% 100800
reload-into-ims
refresh_pattern windowsupdate.com/.*\.(cab|exe) 10080 80% 100800
reload-into-ims
refresh_pattern download.microsoft.com/.*\.(cab|exe) 10080 80% 100800
reload-into-ims
refresh_pattern avast.com/.*\.(vpu|vpaa) 10080 8% 100800 reload-into-ims

This problem make the use of my full bandwidth over 6 hours.

Why im getting refreshing daily? Why around the same time daily?

Thanks!

-- 
Ing. Rogelio C. Sevilla Fernandez
Direccion de Desarrollo Telematico / Secretaria de Administracion
Gobierno del Estado de Colima
Tel (312)3162062 / (312)3162000 ext 2360