[Dovecot] Why does dovecot require the {} password sheme even if there is a $ crypt scheme.

[da-dovecotlist-15 at abelonline.de]

The wiki[1] says:
If all the passwords are in same format, you can use default_pass_scheme to specify it. Otherwise each password needs to be prefixed with "{password-scheme}", for example "{plain}plaintext-password".

Why doesn't dovecot recognize the crypt scheme identifier ($1$ for MD5-CRYPT, $6$ for SHA512-CRYPT etc.)? At the moment I have to have the following in my db for dovecot to work:
{SHA512-CRYPT}$6$salt$passwordhash

[1]http://wiki2.dovecot.org/AuthDatabase/SQL