• 6.5 baseline — 0.6 × season 6.3 (20 gm) + 0.4 × last 10 6.9
• +0.7 opponent leak — they concede 104/game vs a 93.4 league average
• −1.2 at this ground — averages 5.4 there (67 gm)
• vs them: averages 5.1 over 10 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.