• 1.5 baseline — 0.6 × season 1.6 (20 gm) + 0.4 × last 10 1.4
• +0.1 opponent leak — they concede 60.6/game vs a 56.6 league average
• −0.2 at this ground — averages 1.4 there (41 gm)
• vs them: averages 1.3 over 3 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: 5 — far outside his usual range; kept in the average, not smoothed away.