• 1.4 baseline — 0.6 × season 1.3 (18 gm) + 0.4 × last 10 1.5
• −0.2 opponent leak — they concede 10.8/game vs a 12.2 league average
• −0.2 at this ground — averages 1.2 there (42 gm)
• vs them: averages 1.0 over 9 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.