• 12.5 baseline — 0.6 × season 11.5 (6 gm) + 0.4 × last 10 14.1
• +0.6 opponent leak — they concede 386.2/game vs a 369 league average
• +0.7 at this ground — averages 13.2 there (23 gm)
• vs them: averages 10.0 over 2 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 6: 3 — far outside his usual range; kept in the average, not smoothed away.