• 3.7 baseline — 0.6 × season 4.2 (5 gm) + 0.4 × last 10 3.0
• −0.0 opponent leak — they concede 211.7/game vs a 213.6 league average
• +1.3 at this ground — averages 5.1 there (17 gm)
• vs them: averages 3.0 over 1 game — 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 6: 8 — far outside his usual range; kept in the average, not smoothed away.