• 3.0 baseline — 0.6 × season 3.1 (15 gm) + 0.4 × last 10 2.9
• −0.0 opponent leak — they concede 93.2/game vs a 93.4 league average
• +1.0 at this ground — averages 4 there (65 gm)
• vs them: averages 2.9 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 4: 10 — far outside his usual range; kept in the average, not smoothed away.