• 10.6 baseline — 0.6 × season 10.3 (18 gm) + 0.4 × last 10 11.1
• −0.1 opponent leak — they concede 364.1/game vs a 369 league average
• −1.2 at this ground — averages 9.4 there (42 gm)
• vs them: averages 10.2 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 13: 21 — far outside his usual range; kept in the average, not smoothed away.