• 3.2 baseline — 0.6 × season 3.1 (16 gm) + 0.4 × last 10 3.4
• +0.4 opponent leak — they concede 106.2/game vs a 93.4 league average
• +2.3 at this ground — averages 5.5 there (11 gm)
• vs them: averages 6.9 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 17: 7 — far outside his usual range; kept in the average, not smoothed away.