• 3.6 baseline — 0.6 × season 3.7 (9 gm) + 0.4 × last 10 3.6
• +0.3 opponent leak — they concede 166.4/game vs a 155.4 league average
• +0.9 at this ground — averages 4.6 there (12 gm)
• vs them: averages 6.3 over 4 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. Round 9: 7 — far outside his usual range; kept in the average, not smoothed away.