Database Cache and Object Cache settings don't apply

My setup is like this:

Database Cache
Maximum lifetime of cache objects: 18000 seconds
Garbage collection interval: 360000 seconds

Object Cache
Maximum lifetime of cache objects: 18000 seconds
Garbage collection interval: 360000 seconds

But the Database Cache and Object Cache folders are still deleted at 3600 seconds.

What is wrong? Could the hosting provider configured the Apache server Object Cache to delete at 3600 seconds?

http://wordpress.org/extend/plugins/w3-total-cache/