• 7.9 baseline — 0.6 × season 8.1 (15 gm) + 0.4 × last 10 7.6
• −0.2 opponent leak — they concede 209.4/game vs a 213.6 league average
• +0.3 at this ground — averages 8.2 there (67 gm)
• vs them: averages 9.0 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 12: 0 — far outside his usual range; kept in the average, not smoothed away.