• 14.8 baseline — 0.6 × season 14.8 (20 gm) + 0.4 × last 10 14.7
• +1.1 opponent leak — they concede 230.1/game vs a 213.6 league average
• −1.3 at this ground — averages 13.5 there (25 gm)
• vs them: averages 10.6 over 10 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: 6 — far outside his usual range; kept in the average, not smoothed away.