• 7.6 baseline — 0.6 × season 9.3 (4 gm) + 0.4 × last 10 5.2
• +0.4 opponent leak — they concede 225.5/game vs a 213.6 league average
• −2.1 at this ground — averages 5.5 there (4 gm)
• vs them: averages 4.4 over 5 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.