• 4.1 baseline — 0.6 × season 4.1 (19 gm) + 0.4 × last 10 4.0
• −0.1 opponent leak — they concede 22.9/game vs a 23.7 league average
• +4.6 at this ground — averages 8.7 there (51 gm)
• vs them: averages 14.0 over 3 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 10: 16 — far outside his usual range; kept in the average, not smoothed away.