• 26.6 baseline — 0.6 × season 27.1 (15 gm) + 0.4 × last 10 25.8
• −0.6 opponent leak — they concede 360.2/game vs a 369 league average
• −1.1 at this ground — averages 25.5 there (80 gm)
• vs them: averages 25.3 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 15: 1 — far outside his usual range; kept in the average, not smoothed away.