• 0.8 baseline — 0.6 × season 0.7 (18 gm) + 0.4 × last 10 0.9
• +0.0 opponent leak — they concede 13.6/game vs a 12.8 league average
• −0.4 at this ground — averages 0.4 there (14 gm)
• −0.1 wet forecast — averages 0.6 in the wet (8 gm)
• vs them: averages 1.1 over 7 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.