• 6.0 baseline — his last 10 games; only 1 this season, too few to blend
• +0.5 opponent leak — they concede 233.1/game vs a 213.6 league average
• +1.5 at this ground — averages 7.5 there (39 gm)
• +1.2 wet forecast — averages 7.2 in the wet (10 gm)
• vs them: averages 7.2 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.