• 4.4 baseline — 0.6 × season 4.3 (19 gm) + 0.4 × last 10 4.6
• +0.6 opponent leak — they concede 64.2/game vs a 56.6 league average
• −1.3 at this ground — averages 3.1 there (12 gm)
• wet forecast: too thin to count (1 gm) — shown, adds nothing
• vs them: averages 5.2 over 6 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.