• 1.0 baseline — 0.6 × season 0.9 (18 gm) + 0.4 × last 10 1.0
• +0.1 opponent leak — they concede 38.4/game vs a 35.7 league average
• at this ground: too thin to count (2 gm) — shown, adds nothing
• +0.2 wet forecast — averages 1.1 in the wet (14 gm)
• vs them: averages 1.0 over 8 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.