• 3.8 baseline — his last 10 games; only 1 this season, too few to blend
• −0.3 opponent leak — they concede 141.4/game vs a 155.4 league average
• +1.2 at this ground — averages 5 there (6 gm)
• vs them: averages 3.6 over 5 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.