• 1.7 baseline — 0.6 × season 1.5 (13 gm) + 0.4 × last 10 2.0
• −0.1 opponent leak — they concede 22.6/game vs a 23.6 league average
• −1.0 at this ground — averages 0.8 there (26 gm)
• −0.6 wet forecast — averages 1.1 in the wet (14 gm)
• vs them: averages 3.0 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 9: 8 — far outside his usual range; kept in the average, not smoothed away.