• 1.2 baseline — 0.6 × season 1.2 (18 gm) + 0.4 × last 10 1.3
• +0.2 opponent leak — they concede 14.7/game vs a 12.8 league average
• −0.2 at this ground — averages 1.1 there (48 gm)
• vs them: averages 1.3 over 9 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 16: 4 — far outside his usual range; kept in the average, not smoothed away.