• 92.1 baseline — 0.6 × season 86.5 (19 gm) + 0.4 × last 10 100.6
• +1.6 opponent leak — they concede 1715.2/game vs a 1686.6 league average
• −14.6 at this ground — averages 77.5 there (4 gm)
• wet forecast: too thin to count (3 gm) — shown, adds nothing
• vs them: averages 81.3 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.