• 1.2 baseline — 0.6 × season 1.2 (19 gm) + 0.4 × last 10 1.2
• −0.1 opponent leak — they concede 34.1/game vs a 35.7 league average
• −0.4 at this ground — averages 0.8 there (26 gm)
• −0.2 wet forecast — averages 1 in the wet (4 gm)
• vs them: averages 0.5 over 2 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.