• 0.8 baseline — 0.6 × season 0.8 (12 gm) + 0.4 × last 10 0.9
• +0.1 opponent leak — they concede 10.2/game vs a 9.4 league average
• −0.1 at this ground — averages 0.7 there (12 gm)
• −0.8 wet forecast — averages 0 in the wet (5 gm)
• vs them: averages 0.2 over 6 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 5: 3 — far outside his usual range; kept in the average, not smoothed away.