• 19.1 baseline — 0.6 × season 19.1 (10 gm) + 0.4 × last 10 19.1
• +1.1 opponent leak — they concede 1785.8/game vs a 1687.8 league average
• −1.7 at this ground — averages 17.4 there (18 gm)
• vs them: averages 36.0 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 23: 74 — far outside his usual range; kept in the average, not smoothed away.