• 6.4 baseline — 0.6 × season 6.6 (18 gm) + 0.4 × last 10 6.2
• −0.7 opponent leak — they concede 83/game vs a 93.4 league average
• +0.9 at this ground — averages 7.3 there (6 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.