• 31.8 baseline — 0.6 × season 31.8 (21 gm) + 0.4 × last 10 31.8
• +0.3 opponent leak — they concede 347.8/game vs a 344.7 league average
• at this ground: too thin to count (1 gm) — shown, adds nothing
• −4.2 wet forecast — averages 27.6 in the wet (11 gm)
• vs them: averages 29.1 over 10 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 9: 56 — far outside his usual range; kept in the average, not smoothed away.