• 7.3 baseline — 0.6 × season 7.5 (19 gm) + 0.4 × last 10 7.1
• +0.2 opponent leak — they concede 160.7/game vs a 155.4 league average
• −1.0 at this ground — averages 6.4 there (59 gm)
• vs them: averages 7.9 over 9 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.