• 7.4 baseline — 0.6 × season 7.3 (6 gm) + 0.4 × last 10 7.6
• −0.5 opponent leak — they concede 200.3/game vs a 213.6 league average
• +0.9 at this ground — averages 8.4 there (26 gm)
• vs them: averages 9.5 over 4 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.