• 4.1 baseline — 0.6 × season 4.1 (16 gm) + 0.4 × last 10 4.1
• −0.5 opponent leak — they concede 82.5/game vs a 93.4 league average
• +0.6 at this ground — averages 4.7 there (18 gm)
• vs them: averages 2.0 over 2 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.