• 3.4 baseline — 0.6 × season 3.2 (19 gm) + 0.4 × last 10 3.6
• +0.3 opponent leak — they concede 61.9/game vs a 56.6 league average
• −1.0 at this ground — averages 2.4 there (8 gm)
• vs them: averages 1.3 over 9 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: 9 — far outside his usual range; kept in the average, not smoothed away.