• 1.2 baseline — 0.6 × season 1.0 (5 gm) + 0.4 × last 10 1.4
• +0.0 opponent leak — they concede 57.5/game vs a 56.6 league average
• +2.8 at this ground — averages 4 there (49 gm)
• vs them: averages 5.7 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. Finals Week 1: 4 — far outside his usual range; kept in the average, not smoothed away.