• 10.7 baseline — 0.6 × season 10.4 (16 gm) + 0.4 × last 10 11.3
• +0.3 opponent leak — they concede 219.2/game vs a 213.6 league average
• −1.1 at this ground — averages 9.7 there (38 gm)
• vs them: averages 8.9 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.