• 4.8 baseline — 0.6 × season 4.5 (6 gm) + 0.4 × last 10 5.3
• −0.2 opponent leak — they concede 89.3/game vs a 93.4 league average
• −1.2 at this ground — averages 3.6 there (54 gm)
• vs them: averages 4.4 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: 11 — far outside his usual range; kept in the average, not smoothed away.