• 2.4 baseline — 0.6 × season 2.0 (15 gm) + 0.4 × last 10 2.9
• −0.3 opponent leak — they concede 31.2/game vs a 35.3 league average
• −1.4 at this ground — averages 1 there (8 gm)
• wet forecast: too thin to count (2 gm) — shown, adds nothing
• vs them: averages 0.8 over 4 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.