• 12.9 baseline — 0.6 × season 12.7 (13 gm) + 0.4 × last 10 13.2
• −0.7 opponent leak — they concede 201.8/game vs a 213.6 league average
• −1.1 at this ground — averages 11.8 there (70 gm)
• vs them: averages 11.1 over 9 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.