• 5.9 baseline — 0.6 × season 5.9 (10 gm) + 0.4 × last 10 5.9
• +0.3 opponent leak — they concede 224.7/game vs a 213.6 league average
• +1.1 at this ground — averages 7 there (24 gm)
• vs them: averages 8.0 over 2 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.