• 1.0 baseline — 0.6 × season 1.2 (6 gm) + 0.4 × last 10 0.8
• −0.0 opponent leak — they concede 54.9/game vs a 56.6 league average
• +0.2 at this ground — averages 1.2 there (34 gm)
• vs them: averages 2.0 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 15: 5 — far outside his usual range; kept in the average, not smoothed away.