• 41.5 baseline — 0.6 × season 40.8 (18 gm) + 0.4 × last 10 42.5
• −0.6 opponent leak — they concede 339.6/game vs a 344.9 league average
• at this ground: too thin to count (3 gm) — shown, adds nothing
• vs them: averages 25.4 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.