• 1.7 baseline — 0.6 × season 1.5 (16 gm) + 0.4 × last 10 2.0
• −0.3 opponent leak — they concede 19.7/game vs a 23.6 league average
• −1.7 at this ground — averages 0 there (4 gm)
• vs them: averages 0.0 over 7 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 17: 8 — far outside his usual range; kept in the average, not smoothed away. Round 20: 8 — far outside his usual range; kept in the average, not smoothed away.