Sorry if my English too obscure some times...
I meant visual clamping graph.
With many levels walls cut scene too high, and graph being too hard to tune visually.
Hmm, if I remember correctly, walls occlude graph line (with incorrect params), and it's making hard to determine graph form to fix it...
I rechecked game now, and see faint line showing occluded graph sector. You fixed it now or maybe line already exists but too dim to recognize during daytime the first time I played the game.