• 24.1 baseline — 0.6 × season 23.6 (19 gm) + 0.4 × last 10 24.8
• −0.1 opponent leak — they concede 367.1/game vs a 369 league average
• −3.1 at this ground — averages 21 there (4 gm)
• vs them: averages 19.5 over 8 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.