• 6.8 baseline — 0.6 × season 6.4 (16 gm) + 0.4 × last 10 7.4
• +0.5 opponent leak — they concede 166.4/game vs a 155.4 league average
• −0.3 at this ground — averages 6.5 there (8 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.