• 4.8 baseline — 0.6 × season 1.8 (5 gm) + 0.4 × last 10 9.4
• +0.3 opponent leak — they concede 368.1/game vs a 344.7 league average
• at this ground: too thin to count (1 gm) — shown, adds nothing
• vs them: averages 13.0 over 2 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.