The Albin Ballad generally runs a 135% Genoa II which has an area of around 25.4-28sqm, the SA/Disp figure mentioned of 16.09 is based on the 105% Genoa which people run when they don’t need to go fast. The SA/Displacement for the standard genoa II is around 18.71.
The line drawing shows a 105% and a 150% genoa.