• 3.6 baseline — 0.6 × season 3.6 (20 gm) + 0.4 × last 10 3.6
• +0.3 opponent leak — they concede 38.8/game vs a 35.7 league average
• at this ground: too thin to count (1 gm) — shown, adds nothing
• +2.6 wet forecast — averages 6.3 in the wet (8 gm)
• vs them: averages 4.6 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 19: 9 — far outside his usual range; kept in the average, not smoothed away.