Words like "premium" and "superior" subject to opinion. Each breeder rates their fish differently. For example, here's how Sea & Reef categorize their Picassos: "Our Premium Picasso Clownfish has more white markings than our Picasso clownfish and at least two stripes on each side of the fish are joined." And ORA: "Premium Picassos are specimens of superior quality that are hand-selected for their uniqueness. These astounding fish exhibit even greater white coverage than our regular Picassos. Our experienced graders look for premium features such as extra stripes or markings on the face and head that have been recognized as desirable patterns. They always consider the oddness and rarity of the striping, making each fish a unique specimen. Only an extremely small percentage of offspring qualify as ORA Premium Picassos."
The grading system is merely to describe how much white the fish has and if the white areas connect. Grade A Picassos typically have all white areas connecting. Grading in no way implies higher or lower quality. In this case, the female might be Grade B while the male might be Grade A.