• 74.6 baseline — 0.6 × season 74.6 (10 gm) + 0.4 × last 10 74.6
• +1.5 opponent leak — they concede 1722.7/game vs a 1687.8 league average
• −39.6 at this ground — averages 35 there (10 gm)
• −41.4 wet forecast — averages 33.2 in the wet (5 gm)
• vs them: averages 40.3 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 8: 33 — far outside his usual range; kept in the average, not smoothed away.