• 23.6 baseline — 0.6 × season 22.6 (16 gm) + 0.4 × last 10 25.0
• +1.2 opponent leak — they concede 224.7/game vs a 213.6 league average
• −5.7 at this ground — averages 17.9 there (11 gm)
• vs them: averages 17.9 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 20: 39 — far outside his usual range; kept in the average, not smoothed away.