• 16.4 baseline — 0.6 × season 17.1 (14 gm) + 0.4 × last 10 15.4
• −0.1 opponent leak — they concede 367.1/game vs a 369 league average
• +5.4 at this ground — averages 21.8 there (31 gm)
• vs them: averages 19.6 over 7 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 11: 5 — far outside his usual range; kept in the average, not smoothed away.