• 53.2 baseline — 0.6 × season 52.6 (16 gm) + 0.4 × last 10 54.1
• +1.5 opponent leak — they concede 559.8/game vs a 544.6 league average
• −6.1 at this ground — averages 47.1 there (58 gm)
• +4.6 wet forecast — averages 57.8 in the wet (12 gm)
• vs them: averages 51.8 over 12 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. Round 9: 126 — far outside his usual range; kept in the average, not smoothed away.