• 3.0 baseline — 0.6 × season 3.1 (7 gm) + 0.4 × last 10 2.7
• +0.0 opponent leak — they concede 156.4/game vs a 155.4 league average
• −0.5 at this ground — averages 2.5 there (6 gm)
• vs them: averages 0.0 over 1 game — 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.