• 5.6 baseline — 0.6 × season 5.6 (8 gm) + 0.4 × last 8 5.6
• +0.3 opponent leak — they concede 164.6/game vs a 155.4 league average
• +0.1 at this ground — averages 5.8 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.