• 1.5 baseline — 0.6 × season 1.3 (20 gm) + 0.4 × last 10 1.7
• −0.3 opponent leak — they concede 26.6/game vs a 32.7 league average
• +0.6 at this ground — averages 2 there (22 gm)
• vs them: averages 2.0 over 10 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 7: 7 — far outside his usual range; kept in the average, not smoothed away.