• 9.9 baseline — 0.6 × season 10.0 (15 gm) + 0.4 × last 10 9.7
• −0.1 opponent leak — they concede 211.7/game vs a 213.6 league average
• +0.5 at this ground — averages 10.4 there (7 gm)
• vs them: averages 7.0 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.