• 37.7 baseline — 0.6 × season 36.2 (15 gm) + 0.4 × last 10 40.0
• +3.7 opponent leak — they concede 1851.3/game vs a 1687.8 league average
• −0.5 at this ground — averages 37.2 there (26 gm)
• vs them: averages 90.7 over 3 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.