(b) above worked for me. On my last trip to Japan (4/4/19), I reloaded the digital Suica on my iPhone while on the plane, but for some reason the balance didn't update. Once I landed I put it in service mode and the balance updated.

Throughout my trip the balance would not update and I would not get notifications, either when adding money or after exiting a station, unless I put it in service mode, which was extremely annoying. However the Suica card "knew" how much it had on it even if the balance wasn't showing correctly on my iPhone. The CORRECT balance would ALWAYS show on the STATION GATE.

On the last day of my trip, on the way back to Nartia, it started updating the balance correctly and sending me notifications again. I don't think I did anything to fix it, it just fixed itself magically.

I'm headed back on the first ANA A380 return flight to NRT on 5/24, and I'm hoping that my iPhone Suica remembers how to update itself.

Also, I don't see many of the locals using Suica enabled phones. I wonder if they just prefer the physical card.