• 12.5 baseline — 0.6 × season 12.3 (19 gm) + 0.4 × last 10 12.8
• −0.8 opponent leak — they concede 145.2/game vs a 155.4 league average
• −1.5 at this ground — averages 10.9 there (48 gm)
• vs them: averages 12.9 over 8 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.