• 2.8 baseline — 0.6 × season 2.9 (18 gm) + 0.4 × last 10 2.7
• −0.4 opponent leak — they concede 49/game vs a 56.6 league average
• −0.6 at this ground — averages 2.2 there (18 gm)
• vs them: averages 2.0 over 1 game — 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.