+1 confirming that this is how it's worked for me so far (I've owned US shares for about 10 years now), with a US based broker (while living in Japan).
What I have not figured out yet, is how to declare that 10% as a tax credit in Japan. It seems we can, but I've never done it (arg, thinking of all the extra money I've payed in taxes makes me angry, but I'm too lazy to file a claim now).
For JP-based brokers handling US shares: I feel like I'm reading two "conflicting" statements from you retirejapan: it's unclear to me if you say that there is nothing to be done because the accounts do it automatically for us, or if people who want to claim that credit need to do it manually on their tax return form.