• 11.5 baseline — 0.6 × season 11.8 (16 gm) + 0.4 × last 10 11.2
• +0.3 opponent leak — they concede 190.8/game vs a 185.9 league average
• −1.6 at this ground — averages 10 there (56 gm)
• −0.4 wet forecast — averages 11.1 in the wet (14 gm)
• vs them: averages 11.8 over 9 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 21: 0 — far outside his usual range; kept in the average, not smoothed away.