• 13.5 baseline — his last 10 games; only 1 this season, too few to blend
• +0.3 opponent leak — they concede 378.4/game vs a 369 league average
• −1.4 at this ground — averages 12.1 there (7 gm)
• vs them: averages 14.6 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.