usermod not moving home directory

[Steven Stromer]

On fresh install of FC6

usermod -d /home/subdir/[accountname] -m [username]

seems to execute without error, but neither creates the directory 
/home/subdir/[accountname], nor moves any of the files from the original 
location of /home/[accountname]. It does change the account's settings 
to point to /home/subdir/[accountname] as the location of the account's 
home directory. So, it seems like the -d switch is working, and it is 
the -m switch that is not performing properly.

FYI, the /home/subdir directory already exists, and I've tried creating 
the directory /home/subdir/[accountname], and then executing usermod as 
above, all with the same results.

Am I misunderstanding use of the -m switch? Any ideas? Thanks.