• 1.2 baseline — 0.6 × season 1.1 (20 gm) + 0.4 × last 10 1.4
• +0.4 opponent leak — they concede 16.4/game vs a 12.2 league average
• −0.3 at this ground — averages 0.9 there (31 gm)
• −0.9 wet forecast — averages 0.3 in the wet (6 gm)
• vs them: averages 1.3 over 3 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.