• 3.6 baseline — 0.6 × season 3.6 (18 gm) + 0.4 × last 10 3.6
• −0.4 opponent leak — they concede 20.8/game vs a 23.6 league average
• wet forecast: too thin to count (3 gm) — shown, adds nothing
• vs them: averages 2.0 over 4 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 4: 16 — far outside his usual range; kept in the average, not smoothed away.