[azernik]

Why is this a problem? If your password is "foofoo" and was set after the cutoff, then it won't be halved; if it is "foofoo" and was set before the cutoff, it will be halved, and then not match the password in the database, as intended.

[rafekett]

this, i'm not sure why it is hard to see that this is easy to implement without storing passwords in plaintext.

[StavrosK]

You have to have stored the last password change date, which many systems don't do.

[jtheory]

If they didn't before, they can start storing it to implement this.