• 13.1 baseline — 0.6 × season 13.7 (7 gm) + 0.4 × last 10 12.1
• −1.9 opponent leak — they concede 30.1/game vs a 35.3 league average

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.