• 7.3 baseline — 0.6 × season 7.3 (19 gm) + 0.4 × last 10 7.3
• −0.1 opponent leak — they concede 211.7/game vs a 213.6 league average
• +0.2 at this ground — averages 7.5 there (32 gm)
• vs them: averages 7.3 over 4 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.