• 7.5 baseline — 0.6 × season 7.5 (20 gm) + 0.4 × last 10 7.6
• −0.3 opponent leak — they concede 22.6/game vs a 23.6 league average
• −0.8 at this ground — averages 6.7 there (11 gm)
• wet forecast: too thin to count (2 gm) — shown, adds nothing
• vs them: averages 4.0 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 21: 20 — far outside his usual range; kept in the average, not smoothed away.