• 3.4 baseline — 0.6 × season 3.4 (7 gm) + 0.4 × last 10 3.3
• +0.2 opponent leak — they concede 164.6/game vs a 155.4 league average
• +1.0 at this ground — averages 4.4 there (10 gm)
• wet forecast: too thin to count (3 gm) — shown, adds nothing
• vs them: averages 6.0 over 1 game — 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.