rewriter change url after second videocache dir added.

1)
I added new HDD for videocache.
I changed videcache.conf
base_dir = /var/videocache/:120000 | /var/videocache2/:200000

In videocache.log NEW_URL's now are IP/videocache/0/xxxxxxx

2)
Is there a possibility to use 2 or more videcache dirs simultaneously ? or first dir must be full then second can be used?
if i can't use dirs simultaneously size limitation must work perfect but it's not.