• 1.7 baseline — 0.6 × season 1.6 (15 gm) + 0.4 × last 10 1.9
• −0.1 opponent leak — they concede 12.2/game vs a 12.8 league average
• −1.2 at this ground — averages 0.5 there (4 gm)
• −0.9 wet forecast — averages 0.8 in the wet (12 gm)
• vs them: averages 1.3 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. Round 21: 6 — far outside his usual range; kept in the average, not smoothed away.