Skeletal muscle mass per InBody scan. Dashed line = your prior peak. In a BUILD the job is to get back above it and keep climbing.

Already lean. Treat the same-device trend as reliable; absolute % is approximate.

Rough math, not a promise. Trained lifters gain muscle slowly (~0.25-0.5 lb/mo is realistic in a lean surplus), and it needs consistent lifting + protein + a small calorie surplus.