• 8.1 baseline — 0.6 × season 8.3 (18 gm) + 0.4 × last 10 7.9
• +0.4 opponent leak — they concede 164/game vs a 155.4 league average
• at this ground: too thin to count (2 gm) — shown, adds nothing
• vs them: averages 6.6 over 8 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: 15 — far outside his usual range; kept in the average, not smoothed away.