• 7.2 baseline — 0.6 × season 6.9 (15 gm) + 0.4 × last 10 7.6
• −0.5 opponent leak — they concede 145.2/game vs a 155.4 league average
• +3.6 at this ground — averages 10.7 there (7 gm)
• vs them: averages 10.5 over 10 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.