• 9.5 baseline — 0.6 × season 9.8 (13 gm) + 0.4 × last 10 9.2
• −0.1 opponent leak — they concede 210.3/game vs a 213.6 league average
• +0.8 at this ground — averages 10.4 there (56 gm)
• vs them: averages 9.7 over 7 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.