• 1.1 baseline — 0.6 × season 1.1 (19 gm) + 0.4 × last 10 1.2
• +0.0 opponent leak — they concede 36.6/game vs a 35.7 league average
• −0.4 at this ground — averages 0.8 there (14 gm)
• vs them: averages 3.0 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.