• 14.8 baseline — 0.6 × season 15.3 (14 gm) + 0.4 × last 10 14.1
• −0.3 opponent leak — they concede 181.6/game vs a 185.9 league average
• +2.2 at this ground — averages 17 there (57 gm)
• vs them: averages 15.3 over 8 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 13: 4 — far outside his usual range; kept in the average, not smoothed away.