• 5.5 baseline — 0.6 × season 5.0 (14 gm) + 0.4 × last 10 6.3
• −0.1 opponent leak — they concede 181.6/game vs a 185.9 league average
• +0.3 at this ground — averages 5.8 there (9 gm)
• vs them: averages 3.5 over 2 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: 18 — far outside his usual range; kept in the average, not smoothed away.