portsnap refuse

[Fbsd1]

The postsnap says adding refuse statements to select the parts of the 
port tree you have use for will shorten the download process and 
conserve disk space on your host. That only the port categories not 
REFUSED will be selected and compressed for download.

Well for a test I ran portsnap with out any portsnap.conf file. The 
download process took 16 minuets. The I mv portsnap.conf.sample to 
portsnap.conf  and added REFUSE for all the categories except sysutils.

Reran the portsnap and still it took 16 minuets.

What gives here??