• 7.1 baseline — 0.6 × season 7.4 (16 gm) + 0.4 × last 10 6.8
• +0.1 opponent leak — they concede 347.8/game vs a 344.7 league average
• at this ground: too thin to count (1 gm) — shown, adds nothing
• +7.3 wet forecast — averages 14.4 in the wet (10 gm)
• vs them: averages 11.1 over 8 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.