Sc# 4801 Building A Nation Multiple Panes

On 8/8/2013 USPS issued the Building A Nation Pane. In doing so, they provided 5-different MARGIN designs for the same 12 different stamp designs. The individual stamps were given a lower-case alpha designation with the SC# 4801 given to the Sheet. In researching, I find that the individual, differing sheets all carry the same SC# (&appropriate alpha). Any thoughts as to why Scott did not assign something to distinguish the unique differing margin panes? (My latest Scott is the 2022 edition). (Yeah, I know 13+ years later I ask the question, I am surprised I remembered there were 5 different margin panes). Would the complete grouping of 5-panes carry any additional value other than 5x catalog?