• 4.1 baseline — 0.6 × season 4.1 (9 gm) + 0.4 × last 10 4.1
• −0.1 opponent leak — they concede 150.3/game vs a 155.4 league average
• −0.5 at this ground — averages 3.6 there (53 gm)
• vs them: averages 3.0 over 7 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. Opening Round: 0 — far outside his usual range; kept in the average, not smoothed away.