• 10.6 baseline — 0.6 × season 10.0 (20 gm) + 0.4 × last 10 11.4
• −0.2 opponent leak — they concede 209.2/game vs a 213.6 league average
• +0.4 at this ground — averages 10.9 there (19 gm)
• +0.6 wet forecast — averages 11.1 in the wet (8 gm)
• vs them: averages 9.3 over 11 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: 18 — far outside his usual range; kept in the average, not smoothed away.