I have created a shaft opening and used a symbolic line around the void to indicate the actual structural opening as oppose to the finish face opening.

However is it good practice to allow the shaft opening to stop level with the floor finish of the slab it is cutting through or should I increase the top offset by 5mm above the finished floor level?
If I don't increase the top offset my symbolic lines seem to disappear?!

Same for below the slab? where should I allow the shaft opening to finish?