• 182.9 baseline — 0.6 × season 184.3 (18 gm) + 0.4 × last 10 180.7
• −2.6 opponent leak — they concede 1663.5/game vs a 1687.8 league average
• +8.5 at this ground — averages 191.4 there (29 gm)
• vs them: averages 182.6 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.