• 14.0 baseline — 0.6 × season 14.9 (16 gm) + 0.4 × last 10 12.7
• +0.4 opponent leak — they concede 190.8/game vs a 185.9 league average
• +0.2 at this ground — averages 14.2 there (17 gm)
• +2.4 wet forecast — averages 16.4 in the wet (5 gm)
• vs them: averages 16.0 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.