• 5.1 baseline — 0.6 × season 5.2 (9 gm) + 0.4 × last 10 5.0
• +0.4 opponent leak — they concede 101.3/game vs a 93.4 league average
• −0.1 at this ground — averages 5 there (16 gm)
• vs them: averages 5.5 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.