• 24.1 baseline — 0.6 × season 24.0 (9 gm) + 0.4 × last 10 24.3
• +3.1 opponent leak — they concede 39.8/game vs a 35.3 league average
• +5.1 at this ground — averages 29.2 there (11 gm)
• vs them: averages 31.8 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.