• 10.4 baseline — 0.6 × season 10.6 (18 gm) + 0.4 × last 10 10.1
• −0.1 opponent leak — they concede 365.8/game vs a 369 league average
• at this ground: too thin to count (3 gm) — shown, adds nothing
• +1.2 wet forecast — averages 11.6 in the wet (8 gm)
• vs them: averages 10.0 over 9 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: 20 — far outside his usual range; kept in the average, not smoothed away.