• 1.8 baseline — 0.6 × season 1.7 (18 gm) + 0.4 × last 10 1.8
• −0.1 opponent leak — they concede 175.7/game vs a 185.9 league average
• +0.1 at this ground — averages 1.9 there (47 gm)
• vs them: averages 1.5 over 4 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: 5 — far outside his usual range; kept in the average, not smoothed away.