• 1.5 baseline — 0.6 × season 1.4 (14 gm) + 0.4 × last 10 1.6
• −0.1 opponent leak — they concede 22.6/game vs a 23.6 league average
• +0.3 at this ground — averages 1.8 there (55 gm)
• −0.2 wet forecast — averages 1.3 in the wet (12 gm)
• vs them: averages 2.0 over 10 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 6: 8 — far outside his usual range; kept in the average, not smoothed away.