• 16.0 baseline — 0.6 × season 15.5 (6 gm) + 0.4 × last 10 16.8
• +0.4 opponent leak — they concede 377.9/game vs a 369 league average
• +0.5 at this ground — averages 16.5 there (13 gm)
• vs them: averages 17.5 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 6: 1 — far outside his usual range; kept in the average, not smoothed away.