• 3.3 baseline — 0.6 × season 3.2 (12 gm) + 0.4 × last 10 3.4
• −0.0 opponent leak — they concede 154.7/game vs a 155.4 league average
• +1.1 at this ground — averages 4.3 there (45 gm)
• vs them: averages 2.6 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 20: 6 — far outside his usual range; kept in the average, not smoothed away.