• 1.6 baseline — 0.6 × season 1.5 (19 gm) + 0.4 × last 10 1.7
• −0.0 opponent leak — they concede 35.2/game vs a 35.7 league average
• −0.4 at this ground — averages 1.2 there (32 gm)
• vs them: averages 2.0 over 2 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 15: 5 — far outside his usual range; kept in the average, not smoothed away.