• 22.9 baseline — 0.6 × season 24.2 (6 gm) + 0.4 × last 10 21.1
• −0.1 opponent leak — they concede 367.1/game vs a 369 league average
• −4.9 at this ground — averages 18 there (10 gm)
• vs them: averages 14.0 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: 6 — far outside his usual range; kept in the average, not smoothed away.