• 3.4 baseline — his last 10 games; only 2 this season, too few to blend
• −0.3 opponent leak — they concede 51/game vs a 56.6 league average
• +0.6 at this ground — averages 4 there (84 gm)
• vs them: averages 3.4 over 9 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.