• 3.0 baseline — 0.6 × season 3.1 (16 gm) + 0.4 × last 10 2.9
• −0.3 opponent leak — they concede 50.3/game vs a 56.6 league average
• −0.3 at this ground — averages 2.7 there (51 gm)
• vs them: averages 3.8 over 4 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 10: 9 — far outside his usual range; kept in the average, not smoothed away.