I see the difficulty here. ... If I were transcribing a worksheet whose subject was Math and/or Science, I would want to see other worksheets in the series. If some of those worksheets from the same series, did include material that would be transcribed in Nemeth Code (and so would necessitate abiding by the marriage of Braille Formats and Nemeth Code formatting rules), then I would probably transcribe all worksheets from that series following the same formatting rules.
If I were following Guidance and rules very strictly, then for a transcription in UEB which included no Nemeth Code switch indicators, I would follow only Braille Formats formatting rules.
So, if your math worksheet had no Nemeth on it at all, I would try to find a reason to use Nemeth formatting but could support the decision not to.
Thank you for complicating it!