• 6.7 baseline — 0.6 × season 6.4 (15 gm) + 0.4 × last 10 7.1
• −0.3 opponent leak — they concede 203.2/game vs a 213.6 league average
• −0.2 at this ground — averages 6.5 there (15 gm)
• vs them: averages 11.0 over 1 game — 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.