• 1.0 baseline — 0.6 × season 0.8 (20 gm) + 0.4 × last 10 1.4
• +0.1 opponent leak — they concede 38.4/game vs a 35.7 league average
• −0.1 at this ground — averages 0.9 there (11 gm)
• vs them: averages 0.0 over 1 game — 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 18: 4 — far outside his usual range; kept in the average, not smoothed away.