• 133.1 baseline — 0.6 × season 134.8 (14 gm) + 0.4 × last 10 130.5
• +12.9 opponent leak — they concede 1851.3/game vs a 1687.8 league average
• −18.1 at this ground — averages 115 there (4 gm)
• vs them: averages 118.8 over 5 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 9: 5 — far outside his usual range; kept in the average, not smoothed away.