• 1.8 baseline — 0.6 × season 1.9 (13 gm) + 0.4 × last 10 1.6
• −0.2 opponent leak — they concede 81.9/game vs a 93.4 league average
• vs them: averages 2.5 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.