• 5.7 baseline — 0.6 × season 5.5 (16 gm) + 0.4 × last 10 6.0
• +1.2 opponent leak — they concede 28.6/game vs a 23.6 league average
• −2.6 at this ground — averages 3.1 there (9 gm)
• vs them: averages 5.0 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 15: 16 — far outside his usual range; kept in the average, not smoothed away.