• 15.0 baseline — 0.6 × season 15.5 (17 gm) + 0.4 × last 10 14.2
• +0.3 opponent leak — they concede 375.7/game vs a 369 league average
• +1.4 at this ground — averages 16.4 there (59 gm)
• vs them: averages 20.3 over 8 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 6: 25 — far outside his usual range; kept in the average, not smoothed away.