• 4.8 baseline — 0.6 × season 4.8 (6 gm) + 0.4 × last 6 4.8
• +0.4 opponent leak — they concede 230.1/game vs a 213.6 league average
• at this ground: too thin to count (3 gm) — shown, adds nothing

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.