• 9.1 baseline — 0.6 × season 9.1 (20 gm) + 0.4 × last 10 9.0
• −0.0 opponent leak — they concede 212.8/game vs a 213.6 league average
• −1.6 at this ground — averages 7.4 there (16 gm)
• vs them: averages 8.4 over 10 games — evidence, never summed

Most signals here point under while you're on the over — worth reading the working above before you commit.

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.