• 0.1 baseline — his last 10 games; only 1 this season, too few to blend
• +0.0 opponent leak — they concede 13.5/game vs a 12.2 league average
• −0.1 at this ground — averages 0 there (4 gm)
• vs them: averages 0.5 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.