I think having to enter the "old password" in the SSH access section of the web gui is redundant. Often, we need to reset that password because it's been forgotten.
The whole idea to somehow protect unauthorised access becomes obsolete when a simple work around is to enable SSH key and just paste in your public key into the gui. Then you can log in anyway.
I propose this option be removed. If you have access to the webgui you should be able to change root access by password if you have forgotten your login.