• 2.0 baseline — 0.6 × season 1.9 (7 gm) + 0.4 × last 10 2.1
• −0.2 opponent leak — they concede 51/game vs a 56.6 league average
• +0.0 at this ground — averages 2 there (11 gm)
• vs them: averages 3.0 over 2 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 21: 4 — far outside his usual range; kept in the average, not smoothed away.