Mine just has an automatic signature that has
Sincerely,
FirstName LastName, degree/credentials
contact info

He has added a "Good luck!" or a "Have a good weekend!" (or in one infuriating case, when I was upset about his going out of town, "Have a fabulous week!"), but the actual signoff before his name is always "Sincerely." because it's his autosignature, I don't assign any meaning to it. It's actually probably better that way, so I don't think, "Wait, why did he sign it this way this time and a different way the other time?" Because that's totally what I would do...