• 10.5 baseline — 0.6 × season 10.4 (18 gm) + 0.4 × last 10 10.6
• −0.6 opponent leak — they concede 200.8/game vs a 213.6 league average
• vs them: averages 6.0 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.