• 2.3 baseline — 0.6 × season 2.4 (12 gm) + 0.4 × last 10 2.2
• −0.1 opponent leak — they concede 175.7/game vs a 185.9 league average
• +3.8 at this ground — averages 6.1 there (12 gm)
• vs them: averages 6.5 over 2 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.