I'm happy to see your question because there has been much misinterpretation of this rule. Current recommendations under discussion are that you need not divide at every location "higher on the priority list". Regarding the example you sent, you are correct that the (red) baseline indicator attached to the plus symbol should begin the runover line, however it is not necessary to divide again before the final addend (blue). The second example (Example 15.16-4 in the Provisional edition of the Nemeth lesson manual) shows a grouped expression that will not fit on the line. In my opinion, it does not need to be divided further. It is not necessary to divide before the division symbol.
You will be happy to know that the upcoming new edition of the Nemeth Code and the upcoming new edition of the Nemeth instruction manual will be presenting much clearer guidelines to follow when faced with a long mathematical expression that requires division between lines. Until their release, I am happy to address your questions in this forum.