• 5.5 baseline — 0.6 × season 5.7 (9 gm) + 0.4 × last 10 5.3
• +0.1 opponent leak — they concede 157.2/game vs a 155.4 league average
• +0.7 at this ground — averages 6.3 there (40 gm)
• vs them: averages 6.8 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.