• 10.7 baseline — 0.6 × season 10.1 (19 gm) + 0.4 × last 10 11.6
• +0.2 opponent leak — they concede 158.8/game vs a 155.4 league average
• −0.5 at this ground — averages 10.1 there (7 gm)
• vs them: averages 11.0 over 3 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.