• 2.8 baseline — 0.6 × season 2.8 (11 gm) + 0.4 × last 10 2.7
• +0.2 opponent leak — they concede 60.8/game vs a 56.6 league average
• +0.5 at this ground — averages 3.3 there (50 gm)
• vs them: averages 3.4 over 5 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 8: 7 — far outside his usual range; kept in the average, not smoothed away.