回複：NIW RFE reference letter

both of them are fine.
In my response, I included several letters just like previous ones. The only difference is that I focus more on the questions asked by the INS. But I did also include letter which merely address questions in the notice. The letter also stated that the referee know about the notice from me and is willing to address the questions accordingly.
So my suggestion is that you can do both. One letter, especially the one from your boss, can be answer to the questions in the notice. Others can be just like previous but stressing the points in the notice. It makes sense that referee know about the points in the notice since you can easily tell them about that and ask them to discuss the points particularly in the recommendation letters.
Hope that help. Good luck.