• 5.9 baseline — 0.6 × season 6.1 (14 gm) + 0.4 × last 10 5.5
• +0.4 opponent leak — they concede 365.4/game vs a 344.7 league average
• +0.7 at this ground — averages 6.6 there (35 gm)
• vs them: averages 3.3 over 3 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 3: 17 — far outside his usual range; kept in the average, not smoothed away.