After reading the above, I re-visited the file I was having trouble with,
made sure the Roof Tool layer setting was on
, and the addon works as expected. I think you found the simple (albeit undocumented) answer to your question.
MacBook Pro Apple M2 Max, 96 GB of RAM
AC27 US (5003) on Mac OS Ventura 13.6.2
Started on AC4.0 in 91/92/93; full-time user since AC8.1 in 2004