zsh $SHLVL question

[Francisco Borges]

Hello,

I use zsh, and my prompt is set to display the $SHLVL (shell level) if
it's greater than one:

 ~ % zsh
 ~ 2 % zsh
 ~ 3 % zsh
 ~ 4 %

this way I can always know how many shells I've already started.

The problem is that on X at Kubuntu, I always get $SHLVL == 2 at the
first konsole terminal. On Debian I always get $SHLVL == 1. And I can't
see where it comes from:

 5527 ?        Ss     0:00 kdeinit Running...
 5605 ?        R      0:06  \_ konsole [kdeinit]
 5606 pts/1    Ss     0:00      \_ /bin/zsh
 5627 pts/1    S+     0:00      |   \_ ssh -l borges loki.let.rug.nl
 5639 pts/2    Ss     0:00      \_ /bin/zsh
 6283 pts/2    R+     0:00      |   \_ ps fx
 6284 pts/2    D+     0:00      |   \_ /bin/zsh
 6092 pts/3    Ss     0:00      \_ /bin/zsh

Does anybody knows the cause of this?

Any way to avoid it?

-- 
Francisco