I've noticed that when subparts, i.e., part sections added to make one part, the hierarchy takes the name of the first part section and the next added part section flows below the first selection. The logic becomes A + B = A_B
with the two parts A and B taking the name of A. Logically adding A + B should result C as a new part with a new name. However, that is not the case. Hierarchy should control to help for long part sections being joined to make one whole part. Just my two cents.