So I have ECAS access since mine is a paper application
When I logged in through ECAS I saw that the mailing address is mentioned on this tool is of the consultant that I had hired for my PR application.
I received the application on 28th Oct and on 29th I tried to change the mailing address from this consultant to my home address. I followed the steps it said it will take 5 business days to do that. I said well fine, went ahead with it..
Till today the mailing address has not changed

in the ECAS
My citizenship application form has both home and mailing addresses correctly mentioned.
So to answer you in short does changing the address on ECAS works. No is the answer
Alternative is to send the request via the webform(I have not done that)