The transfer of title should be handled by the lien holder, who can also submit for new tags. There should be no reason to pay for the license plate just so you can submit it to the DMV, to cancel the tags as far as I know, since the tags are no longer valid after the lienholder registers the change in ownership.
I think maybe the lot just adds fees for every possible service whether it is necessary or not. If you want to be sure there is nothing more for you to do, you can call your local DMV to check the status of the transfer. I'll add the link for you.