• 10.4 baseline — 0.6 × season 10.8 (14 gm) + 0.4 × last 10 9.8
• −0.7 opponent leak — they concede 343.2/game vs a 369 league average
• +0.8 at this ground — averages 11.2 there (6 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.