from 0.5 baseline, +0.1 at this ground

• 0.5 baseline — 0.6 × season 0.5 (20 gm) + 0.4 × last 10 0.5
• +0.1 opponent leak — they concede 4.4/game vs a 3.5 league average
• +0.1 at this ground — averages 0.6 there against the player's own 0.3 in those same seasons — 282% of that level (22 gm) · held at the ceiling one adjustment is allowed; the raw effect over this sample was larger
• vs them: averages 0.5 over 8 games — 122% of the player's own level in those seasons — evidence, never summed

Derived, not measured — plain arithmetic over 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.