• 1.3 baseline — 0.6 × season 1.3 (9 gm) + 0.4 × last 10 1.3
• +0.2 opponent leak — they concede 64.2/game vs a 56.6 league average
• +0.5 at this ground — averages 1.8 there (11 gm)
• +0.9 wet forecast — averages 2.3 in the wet (4 gm)
• vs them: averages 2.6 over 5 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: 4 — far outside his usual range; kept in the average, not smoothed away.