I guess I'll have to ask the obvious question: what do you mean by "success"?
Last month, I was able to use the system and "change" the address, by providing the same address for both previous and current (since I wasn't sure if my call to NCSC to change my address in 2006 really did what it was supposed to).
After the first address change form was done, I was also able to change the address on my I-485 application (by providing the receipt number).
I don't know if this was "successful" in the sense that all entries pertaining to me have my current address, but I definitely didn't get any errors on the website.