• 27.6 baseline — 0.6 × season 26.0 (21 gm) + 0.4 × last 10 29.9
• +1.9 opponent leak — they concede 368.1/game vs a 344.7 league average
• −2.2 at this ground — averages 25.4 there (10 gm)
• vs them: averages 24.0 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 20: 49 — far outside his usual range; kept in the average, not smoothed away.