• 5.7 baseline — 0.6 × season 5.7 (11 gm) + 0.4 × last 10 5.7
• +0.0 opponent leak — they concede 156.4/game vs a 155.4 league average
• +0.7 at this ground — averages 6.5 there (24 gm)
• vs them: averages 5.3 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.