Thank you for bringing up this topic again -- I am often asked this question. When transcribing a document with the Nemeth Code as the primary code in use throughout the document, we are instructed to follow Braille Formats only when a topic is not discussed in the Nemeth code. The topic of tables is confusing because we are instructed to follow Braille Formats for the construction of tables. Nemeth code rules still apply to the items within the table, however. My advice which you copied from last summer comes directly from NC §57 "Omissions" which gives us directives regarding a blank space that means "information is missing": "When ... a blank space is employed in ink print to denote omission, the general omission symbol must be used in the transcription."