• 0.5 baseline — 0.6 × season 0.4 (20 gm) + 0.4 × last 10 0.6
• +0.0 opponent leak — they concede 13.5/game vs a 12.2 league average
• at this ground: too thin to count (3 gm) — shown, adds nothing
• vs them: averages 0.5 over 2 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 13: 3 — far outside his usual range; kept in the average, not smoothed away.