My understanding is that on a number line, we do not use the numeric indicator at the beginning of a time label below the number line, according to TG guidelines for number lines; but the numeric indicator following the punctuation indicator and colon is used, according to Nemeth Code rules.
Was there an update regarding transcribing time, in that it’s only Nemeth when it’s part of an equation, otherwise no punctuation indicator used before the colon. Of course, I could have misinterpreted the information. I think I saw it on the July 20th 2017 webinar about updates to Nemeth code within UEB.