• 10.1 baseline — 0.6 × season 10.5 (6 gm) + 0.4 × last 10 9.4
• −0.1 opponent leak — they concede 211.2/game vs a 213.6 league average
• −1.6 at this ground — averages 8.5 there (10 gm)
• vs them: averages 9.0 over 1 game — 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 12: 3 — far outside his usual range; kept in the average, not smoothed away.