• 3.0 baseline — 0.6 × season 3.2 (19 gm) + 0.4 × last 10 2.7
• +0.6 opponent leak — they concede 11.6/game vs a 9.7 league average
• vs them: averages 1.4 over 5 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.