• 1.1 baseline — 0.6 × season 1.0 (18 gm) + 0.4 × last 10 1.2
• −0.3 opponent leak — they concede 2.4/game vs a 3.5 league average
• −0.1 at this ground — averages 1 there (5 gm)
• vs them: averages 0.4 over 5 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.