• 63.1 baseline — 0.6 × season 72.0 (16 gm) + 0.4 × last 10 49.8
• +1.1 opponent leak — they concede 1715.2/game vs a 1686.6 league average
• at this ground: too thin to count (2 gm) — shown, adds nothing
• wet forecast: too thin to count (3 gm) — shown, adds nothing
• vs them: averages 48.2 over 5 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.