• 8.0 baseline — 0.6 × season 8.0 (8 gm) + 0.4 × last 10 8.1
• +0.4 opponent leak — they concede 386.2/game vs a 369 league average
• +0.1 at this ground — averages 8.1 there (8 gm)
• vs them: averages 10.5 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.