• 9.2 baseline — 0.6 × season 9.3 (12 gm) + 0.4 × last 10 9.2
• +0.5 opponent leak — they concede 224.7/game vs a 213.6 league average
• +0.6 at this ground — averages 9.8 there (6 gm)
• vs them: averages 9.3 over 6 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 12: 19 — far outside his usual range; kept in the average, not smoothed away.