• 3.9 baseline — 0.6 × season 3.6 (18 gm) + 0.4 × last 10 4.3
• −0.2 opponent leak — they concede 89.3/game vs a 93.4 league average
• −0.2 at this ground — averages 3.7 there (32 gm)
• vs them: averages 4.6 over 5 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 18: 10 — far outside his usual range; kept in the average, not smoothed away.