• 8.9 baseline — 0.6 × season 8.8 (11 gm) + 0.4 × last 10 8.9
• +0.5 opponent leak — they concede 224.7/game vs a 213.6 league average
• −2.3 at this ground — averages 6.6 there (42 gm)
• vs them: averages 6.3 over 3 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.