• 14.3 baseline — 0.6 × season 15.6 (19 gm) + 0.4 × last 10 12.5
• +1.4 opponent leak — they concede 597.6/game vs a 545.7 league average
• +17.0 at this ground — averages 31.4 there (34 gm)
• vs them: averages 32.2 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.