• 25.7 baseline — 0.6 × season 27.1 (18 gm) + 0.4 × last 10 23.6
• −0.5 opponent leak — they concede 338.1/game vs a 344.9 league average
• −8.2 wet forecast — averages 17.5 in the wet (6 gm)
• vs them: averages 24.8 over 5 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: 7 — far outside his usual range; kept in the average, not smoothed away.