• 1.9 baseline — 0.6 × season 1.9 (21 gm) + 0.4 × last 10 2.0
• +0.4 opponent leak — they concede 28.6/game vs a 23.7 league average
• at this ground: too thin to count (1 gm) — shown, adds nothing
• vs them: averages 2.0 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 23: 8 — far outside his usual range; kept in the average, not smoothed away.