• 1.1 baseline — his last 10 games; only 3 this season, too few to blend
• −0.2 opponent leak — they concede 10.3/game vs a 12.2 league average
• +0.1 at this ground — averages 1.2 there (5 gm)
• vs them: averages 1.3 over 7 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.