Can't add new room type to schedule?

[bobo]

I have a schedule which indicates groups room names, areas and area types. However, it wont allow me to add another area type. Normally I would just add a row to an associated schedule and include the new type, but the option for new rows is blanked out. Am i missing something obvious here or is it a bug?

Thanks.

[beegee]

Clicking one of the area type names in the schedule will give you a drop down menu of the area types to choose from.

For Rentable or user-defined area schemes, these are:
Building Common Area
Office Area
Exterior Area
Floor Area
Major Vertical Penetration
Store Area

For Gross Building area schemes, types are:
Gross Building Area
Exterior Area

Area types are an instance property of area tags. Area types contain area measurement rules that apply to area boundaries.

When you create a new area scheme, it uses the type values from the Rentable area scheme.

The area value may change if you change the area type in the Instance Properties of the area tag, or from the schedule menu. This only occurs when the area boundaries apply area rules.