• 4.5 baseline — 0.6 × season 4.5 (20 gm) + 0.4 × last 10 4.7
• −0.2 opponent leak — they concede 150.3/game vs a 155.4 league average
• −0.7 at this ground — averages 3.9 there (40 gm)
• vs them: averages 3.5 over 6 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.