Thanks for the help, Anand!
Wow - that's in black and white, but it's a complete contradiction of our Knowledge Transfer recommendations. I keep Internal Admin as suggested to have access to the Administration tab of the application - so I can adjust analysis and reporting defaults, email addresses to which ETL notices should be sent, refresh the application cache to have it recognize user changes in SMC, etc. Removing the Internal Admin permission has never been mentioned, even in a passing "well, mostly it's supposed to be shut, but.." way.
However, you reminded me to review the emails history for this topic, and I found that I've gotten mixed advice from Tech Support (all concerning my own ID - I was not able to do
08/19/19 - Keep Internal Administrator role and leave out Administrator role to enable the Administration tab in the Quality Analysis Suite (QAS is the heart of the FQA solution) application.
10/10/19 - Keep Internal Administrator role and drop the QAS: Analyst role. The latter has fewer rights than the Internal Administrator role, so it prevents those other rights from being enabled.
I'd like to see Admin vs Internal Admin laid out in a head-to-head comparison, but my post has a second purpose. I also am trying to learn what documentation to look at to learn these things myself. I have our Administration Guide Supplement, spelling out details of our implementation here, but didn't get the Admin Guide itself. I've found a link to BI Admin Guide here, but I've had a hard time finding this and other answers within. If there's an FQA-specific one, I haven't found or been directed to it.