• 12.0 baseline — 0.6 × season 12.1 (15 gm) + 0.4 × last 10 11.8
• −0.7 opponent leak — they concede 175.7/game vs a 185.9 league average
• at this ground: too thin to count (1 gm) — shown, adds nothing
• vs them: averages 16.5 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 19: 5 — far outside his usual range; kept in the average, not smoothed away.