Greetings, Rebecca!
In both examples that you highlight in your attachment, the opening Nemeth Code indicator has been placed on the first line of non-spatial displayed material that does not require special margins instead of at the end of the preceding line of text, because it would not fit at the end of that preceding line.
Although RUEB section 14.6.3 says "When the Nemeth Code text is displayed on one or more lines separate from the UEB text, the Opening Nemeth Code Indicator and the Nemeth Code Terminator may each be placed on a line by itself or at the end of the previous line of text.", this sentence does not list the only allowable placements of the opening Nemeth Code indicator.
In response to your second/subsidiary question, if you were to place the opening Nemeth Code indicator on a line by itself before displayed material, the most appropriate indention would be in the runover position of the text that precedes the displayed material, as you would do if you were inserting an opening Nemeth Code indicator at the end of instructions before a series of exercise items in Nemeth Code.
Thank you for the question, and please do respond with any remaining concerns and/or comments you have.
–Kyle