• 7.9 baseline — 0.6 × season 7.9 (20 gm) + 0.4 × last 10 7.9
• −0.4 opponent leak — they concede 201.8/game vs a 213.6 league average
• +1.6 at this ground — averages 9.5 there (22 gm)
• vs them: averages 8.0 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 6: 14 — far outside his usual range; kept in the average, not smoothed away.