• 2.9 baseline — 0.6 × season 3.2 (15 gm) + 0.4 × last 10 2.4
• −0.1 opponent leak — they concede 22.9/game vs a 23.7 league average
• +1.7 at this ground — averages 4.5 there (45 gm)
• vs them: averages 7.7 over 6 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 23: 12 — far outside his usual range; kept in the average, not smoothed away.