• 2.5 baseline — 0.6 × season 2.5 (18 gm) + 0.4 × last 10 2.4
• +0.3 opponent leak — they concede 64.2/game vs a 56.6 league average
• −0.0 at this ground — averages 2.4 there (16 gm)
• −0.2 wet forecast — averages 2.3 in the wet (7 gm)
• vs them: averages 3.3 over 11 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 21: 7 — far outside his usual range; kept in the average, not smoothed away.