• 1.7 baseline — 0.6 × season 1.8 (15 gm) + 0.4 × last 10 1.6
• +0.6 opponent leak — they concede 16.4/game vs a 12.2 league average
• −0.6 at this ground — averages 1.1 there (51 gm)
• vs them: averages 1.0 over 8 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: 5 — far outside his usual range; kept in the average, not smoothed away.