• 8.0 baseline — 0.6 × season 8.0 (6 gm) + 0.4 × last 10 8.0
• −0.2 opponent leak — they concede 209.4/game vs a 213.6 league average
• −0.7 at this ground — averages 7.3 there (7 gm)
• vs them: averages 5.7 over 3 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.