• 6.6 baseline — 0.6 × season 6.6 (12 gm) + 0.4 × last 10 6.6
• +0.4 opponent leak — they concede 389.2/game vs a 369 league average
• +1.2 at this ground — averages 7.8 there (5 gm)
• wet forecast: too thin to count (1 gm) — shown, adds nothing
• vs them: averages 9.0 over 1 game — 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.