• 1.8 baseline — 0.6 × season 1.8 (12 gm) + 0.4 × last 10 1.8
• −0.2 opponent leak — they concede 49/game vs a 56.6 league average
• −0.3 at this ground — averages 1.5 there (6 gm)

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 18: 6 — far outside his usual range; kept in the average, not smoothed away.