I've tried when it is J0 - but I take the approach (even if J>1) of doing both steps on the phone, so if it can't be done the phone rep tells me. I haven't had any problems explaining what I'm doing.

I think there was one occasion when I succeeded in a J0 situation. But of course I can't be sure; perhaps it went to J1 between when I checked and when I called in. So it doesn't hurt to ask, even when J0.