• 2.1 baseline — 0.6 × season 2.0 (20 gm) + 0.4 × last 10 2.3
• +0.1 opponent leak — they concede 13.6/game vs a 12.8 league average
• −0.9 at this ground — averages 1.3 there (34 gm)
• vs them: averages 1.0 over 6 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.