• 21.8 baseline — his last 10 games; only 1 this season, too few to blend
• −0.0 opponent leak — they concede 35.3/game vs a 35.3 league average
• +1.9 at this ground — averages 23.7 there (6 gm)
• vs them: averages 22.4 over 9 games — evidence, never summed

Derived, not measured — plain arithmetic over his real games, shown in full. Adjustments can overlap (a game at this ground can also be a wet one); they add simply, and this note is the admission.