• 4.1 baseline — 0.6 × season 4.0 (15 gm) + 0.4 × last 10 4.2
• +0.3 opponent leak — they concede 100.5/game vs a 93.4 league average
• −1.3 at this ground — averages 2.8 there (9 gm)
• vs them: averages 3.3 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: 1 — far outside his usual range; kept in the average, not smoothed away.