The timeline I listed in Plaidypus is correct
Lucifer is the Lord of Lies, and him (and his minions) cut their teeth on lying .
If you want to know why Lucifer might lie about it, consider the lab incident with the vampire. Start doing some deductive thinking on why.
Plaidypus does happen prior to the events of Client from Hell, and Lucifer is the Lord of Lies for a reason.
I hope that offers some clarity!