• 10.8 baseline — 0.6 × season 11.0 (20 gm) + 0.4 × last 10 10.5
• −0.5 opponent leak — they concede 148.3/game vs a 155.4 league average
• −2.1 at this ground — averages 8.7 there (25 gm)
• vs them: averages 9.0 over 2 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.