• 0.9 baseline — 0.6 × season 0.9 (20 gm) + 0.4 × last 10 0.9
• +0.0 opponent leak — they concede 33.5/game vs a 32.7 league average
• +0.1 at this ground — averages 1 there (13 gm)
• vs them: averages 3.4 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 14: 3 — far outside his usual range; kept in the average, not smoothed away.