• 2.7 baseline — 0.6 × season 2.6 (16 gm) + 0.4 × last 10 3.0
• −0.2 opponent leak — they concede 494.6/game vs a 544.2 league average
• +3.8 at this ground — averages 6.5 there (26 gm)
• vs them: averages 10.0 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: 10 — far outside his usual range; kept in the average, not smoothed away.