• 7.6 baseline — 0.6 × season 7.5 (20 gm) + 0.4 × last 10 7.7
• −0.3 opponent leak — they concede 148.3/game vs a 155.4 league average
• +0.2 at this ground — averages 7.8 there (64 gm)
• vs them: averages 7.4 over 9 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.