• 6.2 baseline — 0.6 × season 6.0 (7 gm) + 0.4 × last 10 6.5
• −0.1 opponent leak — they concede 211.2/game vs a 213.6 league average
• +2.0 at this ground — averages 8.2 there (24 gm)
• vs them: averages 9.3 over 6 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.