• 5.1 baseline — 0.6 × season 4.9 (20 gm) + 0.4 × last 10 5.5
• −0.3 opponent leak — they concede 145.2/game vs a 155.4 league average
• at this ground: too thin to count (2 gm) — shown, adds nothing
• vs them: averages 5.0 over 3 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 18: 13 — far outside his usual range; kept in the average, not smoothed away.