• 82.4 baseline — 0.6 × season 79.2 (13 gm) + 0.4 × last 10 87.1
• +1.4 opponent leak — they concede 1715.2/game vs a 1686.6 league average
• at this ground: too thin to count (3 gm) — shown, adds nothing
• +12.6 wet forecast — averages 95 in the wet (7 gm)
• vs them: averages 113.2 over 6 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.