• 5.2 baseline — 0.6 × season 5.0 (12 gm) + 0.4 × last 10 5.4
• −0.6 opponent leak — they concede 82.1/game vs a 93.4 league average
• −1.5 at this ground — averages 3.7 there (45 gm)
• vs them: averages 4.2 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 19: 11 — far outside his usual range; kept in the average, not smoothed away.