• 1.3 baseline — 0.6 × season 1.3 (20 gm) + 0.4 × last 10 1.3
• +0.0 opponent leak — they concede 33.1/game vs a 32.8 league average
• +0.1 at this ground — averages 1.4 there (8 gm)
• vs them: averages 1.6 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 23: 5 — far outside his usual range; kept in the average, not smoothed away.