• 10.6 baseline — 0.6 × season 10.6 (9 gm) + 0.4 × last 10 10.7
• +0.1 opponent leak — they concede 349.4/game vs a 344.7 league average
• +1.6 at this ground — averages 12.2 there (5 gm)
• vs them: averages 5.8 over 4 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.