• 41.8 baseline — 0.6 × season 41.8 (10 gm) + 0.4 × last 10 41.8
• +3.7 opponent leak — they concede 1838.8/game vs a 1687.8 league average
• +30.6 at this ground — averages 72.4 there (10 gm)
• vs them: averages 80.3 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 3: 95 — far outside his usual range; kept in the average, not smoothed away.