• 12.9 baseline — 0.6 × season 12.8 (15 gm) + 0.4 × last 10 13.1
• −0.1 opponent leak — they concede 367.1/game vs a 369 league average
• −2.1 at this ground — averages 10.8 there (33 gm)
• vs them: averages 11.4 over 9 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 8: 26 — far outside his usual range; kept in the average, not smoothed away.