• 2.5 baseline — 0.6 × season 2.5 (20 gm) + 0.4 × last 10 2.6
• −0.2 opponent leak — they concede 30.6/game vs a 32.8 league average
• −0.3 at this ground — averages 2.2 there (13 gm)
• vs them: averages 0.7 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 22: 9 — far outside his usual range; kept in the average, not smoothed away.