• 8.1 baseline — his last 10 games; only 1 this season, too few to blend
• +0.4 opponent leak — they concede 389.2/game vs a 369 league average
• +2.5 at this ground — averages 10.6 there (9 gm)
• vs them: averages 10.4 over 8 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.