• 6.5 baseline — 0.6 × season 6.7 (7 gm) + 0.4 × last 10 6.3
• +0.6 opponent leak — they concede 101.3/game vs a 93.4 league average
• −0.9 at this ground — averages 5.6 there (38 gm)
• vs them: averages 6.9 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.