About "another code" I second Mr. Dave Diehl opinion in the last post of
http://forums.coade.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=74610

About B31.8, a good reference may be a conference paper with title
MOP, MAOP, DP and MAWP- UNDERSTANDING THE DIFFERENCES TO AVOID UNNECESSARY COSTS by John Aumuller and Vincent Carucci, just google the title and you may find it. There isn't an ultimate answer to your questions, but at least the article would bring some light in your decisions. You may carefully review B31.8 2018 edn as well.