• 13.0 baseline — 0.6 × season 12.2 (13 gm) + 0.4 × last 10 14.2
• +1.2 opponent leak — they concede 594.4/game vs a 545.7 league average
• −4.7 at this ground — averages 8.3 there (4 gm)
• vs them: averages 32.4 over 5 games — evidence, never summed

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 11: 36 — far outside his usual range; kept in the average, not smoothed away.