• 9.1 baseline — 0.6 × season 8.5 (15 gm) + 0.4 × last 10 10.0
• +0.0 opponent leak — they concede 186.4/game vs a 185.9 league average
• at this ground: too thin to count (3 gm) — shown, adds nothing
• −2.7 wet forecast — averages 6.4 in the wet (9 gm)
• vs them: averages 10.5 over 2 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.