• 5.4 baseline — 0.6 × season 5.4 (5 gm) + 0.4 × last 10 5.5
• −0.1 opponent leak — they concede 211.2/game vs a 213.6 league average
• +0.6 at this ground — averages 6 there (20 gm)
• vs them: averages 4.0 over 3 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.