• 51.5 baseline — 0.6 × season 49.7 (20 gm) + 0.4 × last 10 54.3
• +4.6 opponent leak — they concede 1838.8/game vs a 1687.8 league average
• −10.7 at this ground — averages 40.8 there (12 gm)
• vs them: averages 41.1 over 7 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 16: 126 — far outside his usual range; kept in the average, not smoothed away.