• 0.4 baseline — 0.6 × season 0.4 (7 gm) + 0.4 × last 7 0.4
• +0.0 opponent leak — they concede 36.6/game vs a 35.7 league average
• +0.3 at this ground — averages 0.8 there (4 gm)

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.