• 4.8 baseline — 0.6 × season 5.1 (12 gm) + 0.4 × last 10 4.5
• +0.0 opponent leak — they concede 157/game vs a 155.4 league average
• −0.4 at this ground — averages 4.4 there (9 gm)
• vs them: averages 5.0 over 13 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.