• 7.9 baseline — 0.6 × season 8.0 (15 gm) + 0.4 × last 10 7.8
• −0.2 opponent leak — they concede 360.2/game vs a 369 league average
• +2.6 at this ground — averages 10.5 there (22 gm)
• vs them: averages 11.7 over 7 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.