• 11.0 baseline — 0.6 × season 10.6 (15 gm) + 0.4 × last 10 11.7
• +0.5 opponent leak — they concede 386.2/game vs a 369 league average
• −1.7 at this ground — averages 9.4 there (40 gm)
• vs them: averages 10.3 over 8 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.