• 2.8 baseline — 0.6 × season 2.8 (18 gm) + 0.4 × last 10 2.8
• +0.1 opponent leak — they concede 351.8/game vs a 344.7 league average
• +0.2 at this ground — averages 3 there (29 gm)
• vs them: averages 4.5 over 8 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: 7 — far outside his usual range; kept in the average, not smoothed away.