• 0.8 baseline — 0.6 × season 0.7 (20 gm) + 0.4 × last 10 0.9
• +0.1 opponent leak — they concede 39/game vs a 35.7 league average
• +0.6 at this ground — averages 1.4 there (63 gm)
• vs them: averages 1.2 over 6 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 13: 3 — far outside his usual range; kept in the average, not smoothed away.