• 4.5 baseline — 0.6 × season 4.5 (10 gm) + 0.4 × last 10 4.5
• −0.1 opponent leak — they concede 209.4/game vs a 213.6 league average
• vs them: averages 6.0 over 2 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.