I have run across another answer in the book that I need help understanding. The book has a good section in the back explaining the reasons for the chosen codes, but on this one it doesn't specify the sequencing reasons. I am coding for anesthesia here. The answer is 00567-AA-P5,99140, 36556-59, 93503, T82.897A,125.10. I understand why they are using the modifier 59 on 36556, but I don't understand why they have sequenced 36556 before 93503. 93503 has a higher RVU and is also considered the "parent" code here. Any help is appreciated!!