• 1.1 baseline — 0.6 × season 1.0 (19 gm) + 0.4 × last 10 1.3
• −0.1 opponent leak — they concede 12.2/game vs a 12.8 league average
• +0.4 at this ground — averages 1.6 there (25 gm)
• vs them: averages 0.9 over 10 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.