• 4.8 baseline — 0.6 × season 4.8 (18 gm) + 0.4 × last 10 4.7
• −0.2 opponent leak — they concede 88.8/game vs a 93.4 league average
• at this ground: too thin to count (1 gm) — shown, adds nothing
• −1.0 wet forecast — averages 3.8 in the wet (8 gm)
• vs them: averages 5.1 over 10 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 8: 10 — far outside his usual range; kept in the average, not smoothed away.