• 7.6 baseline — 0.6 × season 8.1 (20 gm) + 0.4 × last 10 6.8
• −0.8 opponent leak — they concede 83/game vs a 93.4 league average
• −2.9 at this ground — averages 4.7 there (18 gm)
• vs them: averages 5.3 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 2: 19 — far outside his usual range; kept in the average, not smoothed away.