Bob one of the reasons I don`t lock my plate down in the table is so I can take the router out when I`m not using it so that the weight isn`t hanging on it. You can always try taking it out and suspending it on the face, upside down i.e., and let it bend back the other way. It will take time but if it bent one way it will bend back again and be at least close to flat again.
Someone I consider a master woodworker once told me that a master woodworker is not someone who never makes mistakes. He is someone who is able to cover them up so that no one can tell.