• 4.3 baseline — 0.6 × season 3.9 (19 gm) + 0.4 × last 10 4.8
• −0.1 opponent leak — they concede 152.3/game vs a 155.4 league average
• −0.7 at this ground — averages 3.6 there (78 gm)
• vs them: averages 3.1 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: 9 — far outside his usual range; kept in the average, not smoothed away.