• 3.4 baseline — 0.6 × season 3.5 (17 gm) + 0.4 × last 10 3.3
• −0.5 opponent leak — they concede 49/game vs a 56.6 league average
• +0.1 at this ground — averages 3.5 there (32 gm)
• vs them: averages 2.4 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 18: 14 — far outside his usual range; kept in the average, not smoothed away.