I would say Sugar Mag and SSDD are the same song especially if they are played in succession. If they play Sugar Mag and then a few songs later finish up with SSDD then they could be separate songs. It's surprising to see them write the set list out as Sugar Mag>SSDD to end the show last night.
I would say that you are entitled to your opinion. It used to be mine before a recent (today) adjustment. Since SSDD is not always linked, I would agree with the set list just as the band displays it. (When I list Sugar Magnolia in a set list, I assume that it includes SSDD. Now I know to list them separately.)