• 7.2 baseline — 0.6 × season 6.9 (15 gm) + 0.4 × last 10 7.6
• +0.5 opponent leak — they concede 166.4/game vs a 155.4 league average
• +2.0 at this ground — averages 9.2 there (51 gm)
• +1.1 wet forecast — averages 8.3 in the wet (13 gm)
• vs them: averages 8.3 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.