• 13.3 baseline — his last 10 games; only 3 this season, too few to blend
• −0.2 opponent leak — they concede 364.1/game vs a 369 league average
• −0.7 at this ground — averages 12.6 there (44 gm)
• vs them: averages 13.8 over 4 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.