• 2.8 baseline — 0.6 × season 2.7 (18 gm) + 0.4 × last 10 2.8
• +0.4 opponent leak — they concede 64.2/game vs a 56.6 league average
• +1.5 at this ground — averages 4.3 there (14 gm)
• +0.9 wet forecast — averages 3.6 in the wet (8 gm)
• vs them: averages 4.3 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: 9 — far outside his usual range; kept in the average, not smoothed away.