• 10.5 baseline — 0.6 × season 10.3 (7 gm) + 0.4 × last 10 10.8
• −0.1 opponent leak — they concede 211.7/game vs a 213.6 league average
• at this ground: too thin to count (3 gm) — shown, adds nothing
• +2.1 wet forecast — averages 12.6 in the wet (12 gm)
• vs them: averages 11.6 over 7 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.