On the sizing form, HyperSizer reports all weights in terms of unit weight (lb/sq ft), therefore from this calculation, to get total panel weight, you do need to multiply this number times the panel area.
However, on the Summary tab of the Project setup form, in the tree on the left hand side of this tab, you can get the total weight for any component, group, or assembly where this calculation has been done for you.
When Hypersizer calculates the total component area, it uses the total summed area from the elements making up that component. The component area appears on the lower left hand corner of the sizing form. It DOES NOT use the a and b lengths. These lengths are used for buckling analysis and pressure analysis only. Therefore, changing the a and b lengths will not affect the panel area or total weight.
Note that for workspace analyses (i.e. without a finite element model), HyperSizer assumes that all panels are exactly 1 sq ft in area. Therefore to get the total weight for a panel in a workspace, you must manually multiply HyperSizer's reported unit weight by the panel area.