• 22.9 baseline — 0.6 × season 23.5 (14 gm) + 0.4 × last 10 22.1
• +3.1 opponent leak — they concede 40/game vs a 35.3 league average
• +0.5 at this ground — averages 23.5 there (75 gm)
• vs them: averages 28.7 over 7 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 17: 8 — far outside his usual range; kept in the average, not smoothed away.