I have the answer!
Although my information was correct at the time the spring Bulletin was published, it is now out-of-date.
Recent changes (which are not even published yet on BANA's website) to the Guidance for Transcription Using the Nemeth Code within UEB Contexts change how measurement units are included or excluded from Nemeth switch indicators.
So, the content of "AN INTRODUCTION TO BRAILLE MATHEMATICS, Using UEB and the Nemeth Code, Provisional Online Edition 2017" is correct and up-to-date. And the summary statement from the spring Bulletin article should be changed to:
When next to a number that belongs in Nemeth Code, a related abbreviated measurement unit is transcribed within Nemeth Code, but a container or amount that does not have a fixed definition, whether spelled out or abbreviated, is not.
in addition to examples and other content of the article being updated.
Thank you again for pointing this out!
Please watch BANA's website for the updated Guidance document to be published.