• 3.8 baseline — 0.6 × season 3.9 (16 gm) + 0.4 × last 10 3.7
• +0.3 opponent leak — they concede 39/game vs a 35.7 league average
• −1.8 at this ground — averages 2 there (8 gm)
• −0.2 wet forecast — averages 3.7 in the wet (6 gm)
• vs them: averages 4.0 over 4 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 8: 11 — far outside his usual range; kept in the average, not smoothed away.