• 0.5 baseline — 0.6 × season 0.7 (19 gm) + 0.4 × last 10 0.2
• +0.1 opponent leak — they concede 15.8/game vs a 12.2 league average
• +0.0 at this ground — averages 0.5 there (36 gm)
• −0.4 wet forecast — averages 0.1 in the wet (15 gm)
• vs them: averages 1.1 over 8 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 9: 4 — far outside his usual range; kept in the average, not smoothed away.