They were producing a little less than one bomb per month at that time. I believe the third attack was planned for sometime in mid-September. Later on, after the war, plutonium production dropped off due to a reactor problem called the “Wigner effect,” so that one-per-month rate wouldn’t have been sustainable until that issue was solved.
We’re also lucky somebody didn’t bump off Hirohito to make him a “martyr”.
Thanks Campton.