• 16.5 baseline — 0.6 × season 15.9 (20 gm) + 0.4 × last 10 17.4
• +0.1 opponent leak — they concede 156.4/game vs a 155.4 league average
• −2.3 at this ground — averages 14.2 there (40 gm)
• vs them: averages 14.0 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 16: 26 — far outside his usual range; kept in the average, not smoothed away.