• 3.5 baseline — 0.6 × season 2.9 (17 gm) + 0.4 × last 10 4.3
• −0.0 opponent leak — they concede 185.2/game vs a 185.9 league average
• −0.3 at this ground — averages 3.2 there (6 gm)
• vs them: averages 0.0 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 20: 12 — far outside his usual range; kept in the average, not smoothed away.