I never got a definitive answer to this question. I even spoke to an actual IRS person and she described the process of handling returns and amended returns which jibed with my understanding (that ordinary returns are processed in a few weeks, and amended returns would take up to 16 weeks), but she never responded to my description of events by affirming that I handled it correctly. So I'm proceeding on the assumption that TT is wrong and I don't need to follow up my e-file of an amended reeturn with a paper return.
